How to print: choose double-sided (duplex), flip on long edge, A4, scale 100%. Each sheet of nine fronts is followed by its sheet of backs, mirrored so they line up when cut. 118 cards on 14 double-sided pages. The facts come from the site's element write-ups.
Lithium is the lightest metal and the least dense solid element.
Lithium was one of only three elements created in significant amounts in the Big Bang.
In a flame test lithium burns a deep crimson, and lithium compounds are used to colour red fireworks.
periodicbubbles.com/element/lithium.html
Helium He · 2
Helium was identified in sunlight in 1868, decades before it was found on Earth.
Liquid helium cooled below about minus 271 degrees Celsius becomes a superfluid with zero viscosity that can climb the walls of an open container.
Every alpha particle emitted by a radioactive atom is a helium nucleus, so most helium on Earth is the product of radioactive decay.
periodicbubbles.com/element/helium.html
Hydrogen H · 1
Around three quarters of the ordinary matter in the universe, by mass, is hydrogen.
Hydrogen has three natural isotopes. Ordinary hydrogen has no neutron, deuterium has one, and tritium has two and is radioactive.
Water made with deuterium instead of ordinary hydrogen is called heavy water. Ice made from it sinks in normal water.
periodicbubbles.com/element/hydrogen.html
Carbon C · 6
Diamond and graphite are both pure carbon, yet one is the hardest natural material and the other is soft enough to write with.
Graphene, a single layer of carbon atoms, earned Andre Geim and Konstantin Novoselov the Nobel Prize in Physics in 2010. They first peeled it from graphite with sticky tape.
Carbon-14 has a half-life of about 5,730 years, which is what makes radiocarbon dating possible.
periodicbubbles.com/element/carbon.html
Boron B · 5
Boron is one of very few elements not made inside stars. Almost all of it comes from cosmic rays splitting heavier atoms apart.
Boron compounds burn with a bright green flame, and boric acid is used to colour green fireworks.
Borosilicate glass, developed in the 1890s, is used for laboratory glassware because it barely expands when heated.
periodicbubbles.com/element/boron.html
Beryllium Be · 4
Emerald and aquamarine are both the mineral beryl, a beryllium aluminium silicate. Traces of chromium make emerald green and traces of iron make aquamarine blue.
James Chadwick discovered the neutron in 1932 by firing alpha particles at a beryllium target.
The mirror of the James Webb Space Telescope is made from beryllium coated with a thin layer of gold.
periodicbubbles.com/element/beryllium.html
Fluorine F · 9
Fluorine is the most electronegative element, with a Pauling value of 3.98.
Henri Moissan, who first isolated fluorine in 1886, won the Nobel Prize in Chemistry for it in 1906.
PTFE, the non-stick coating, was discovered by accident in 1938 when Roy Plunkett found that a fluorine-containing gas had turned into a waxy solid inside its cylinder.
periodicbubbles.com/element/fluorine.html
Oxygen O · 8
Oxygen is the most abundant element in the Earth's crust, making up about 46 per cent of it by mass.
About 65 per cent of the mass of the human body is oxygen, mostly as water.
Liquid oxygen is pale blue and will hang between the poles of a strong magnet.
periodicbubbles.com/element/oxygen.html
Nitrogen N · 7
About 78 per cent of the air by volume is nitrogen.
The triple bond in a nitrogen molecule is one of the strongest chemical bonds known, which is why nitrogen gas is so unreactive.
Nitrogen fertiliser made by the Haber-Bosch process is estimated to feed around half of the world's population.
periodicbubbles.com/element/nitrogen.html
10
Ne
Neon
20.17976 u · Noble gas
11
Na
Sodium
22.989769282 u · Alkali metal
12
Mg
Magnesium
24.305 u · Alkaline earth metal
13
Al
Aluminium
26.98153857 u · Post-transition metal
14
Si
Silicon
28.085 u · Metalloid
15
P
Phosphorus
30.9737619985 u · Polyatomic non-metal
16
S
Sulfur
32.06 u · Polyatomic non-metal
17
Cl
Chlorine
35.45 u · Diatomic non-metal
18
Ar
Argon
39.9481 u · Noble gas
Magnesium Mg · 12
Every chlorophyll molecule has a magnesium ion at its centre, so photosynthesis depends on magnesium.
Burning magnesium cannot be extinguished with water or carbon dioxide because it reacts with both.
Magnesium is the third most abundant element dissolved in seawater, after chlorine and sodium.
periodicbubbles.com/element/magnesium.html
Sodium Na · 11
Sodium is soft enough to cut with a knife and floats on water, where it fizzes and often catches fire.
Sodium street lamps glow orange because excited sodium atoms emit light at a wavelength close to 589 nanometres.
The symbol Na comes from natrium, after natron, the mineral the ancient Egyptians used to dry out mummies.
periodicbubbles.com/element/sodium.html
Neon Ne · 10
Neon is the fifth most abundant element in the universe, but only about 18 parts per million of Earth's air.
Only the red-orange colour in a neon sign actually comes from neon. Other colours use different gases or coated glass.
Neon has the narrowest liquid range of any element, less than three degrees between melting and boiling.
periodicbubbles.com/element/neon.html
Phosphorus P · 15
Phosphorus was the first element discovered by a named individual, Hennig Brand, in about 1669.
White phosphorus glows in the dark because it reacts slowly with oxygen in the air, not because it stores light.
The word phosphorescence was named after phosphorus, even though the glow of phosphorus is a different process.
periodicbubbles.com/element/phosphorus.html
Silicon Si · 14
Silicon makes up about 28 per cent of the Earth's crust by mass, second only to oxygen.
Like water, silicon expands as it freezes, so solid silicon floats on molten silicon.
Silicon Valley in California is named after the element because of the semiconductor firms that gathered there.
periodicbubbles.com/element/silicon.html
Aluminium Al · 13
In the 1850s aluminium cost more than gold, and Napoleon III is said to have served his most honoured guests with aluminium cutlery.
The small pyramid on top of the Washington Monument, set in 1884, is made of aluminium, then a showpiece metal.
Rubies and sapphires are crystals of aluminium oxide coloured by tiny amounts of other elements.
periodicbubbles.com/element/aluminium.html
Argon Ar · 18
Argon was the first noble gas to be discovered, and its discovery earned Nobel Prizes in both physics and chemistry in the same year, 1904.
Almost all of Earth's argon was made by the radioactive decay of potassium in rocks, and potassium-argon dating uses that build-up to work out the age of ancient lava flows.
In 2000 chemists in Finland made argon fluorohydride, the first true compound of argon, but it only survives at temperatures far below -250 °C.
periodicbubbles.com/element/argon.html
Chlorine Cl · 17
Chlorine was the first chemical agent used on a large scale in war, released from cylinders at Ypres in April 1915.
The swimming pool smell most people call chlorine is mostly chloramines, formed when chlorine reacts with sweat and urine; a well-kept pool smells of very little.
A single chlorine atom released from a CFC in the stratosphere can destroy many thousands of ozone molecules before it is finally removed.
periodicbubbles.com/element/chlorine.html
Sulfur S · 16
Sulfur has more solid forms, or allotropes, than any other element; the familiar yellow crystals are made of rings of eight atoms.
When molten sulfur is heated further it becomes darker and thicker instead of thinner, because the rings break open and tangle into long chains.
Sulfur burns with a blue flame, which is why brimstone became so closely linked with fire in old writings.
periodicbubbles.com/element/sulfur.html
19
K
Potassium
39.09831 u · Alkali metal
20
Ca
Calcium
40.0784 u · Alkaline earth metal
21
Sc
Scandium
44.9559085 u · Transition metal
22
Ti
Titanium
47.8671 u · Transition metal
23
V
Vanadium
50.94151 u · Transition metal
24
Cr
Chromium
51.99616 u · Transition metal
25
Mn
Manganese
54.9380443 u · Transition metal
26
Fe
Iron
55.8452 u · Transition metal
27
Co
Cobalt
58.9331944 u · Transition metal
Scandium Sc · 21
Mendeleev predicted scandium in 1869 as ekaboron with an atomic weight near 44; the measured value is 44.96.
Scandium is the lightest of all the transition metals, with a density only slightly greater than aluminium.
Aluminium-scandium alloys were developed in the Soviet Union and used in MiG fighter aircraft before appearing in sporting goods.
periodicbubbles.com/element/scandium.html
Calcium Ca · 20
Cement manufacture is one of the largest single industrial sources of carbon dioxide, because heating limestone drives off the gas chemically as well as burning fuel.
Calcium colours a flame brick red, which is how it shows up in a flame test and in some fireworks.
Your skeleton is not fixed: bone is constantly dissolved and rebuilt, so the calcium in it is replaced over a period of years.
periodicbubbles.com/element/calcium.html
Potassium K · 19
About one atom in every eight thousand of natural potassium is radioactive potassium-40, and the potassium in an adult body produces thousands of radioactive decays every second.
Bananas are rich enough in potassium that the informal banana equivalent dose is sometimes used to put small radiation exposures into perspective.
Potassium burns with a lilac flame, which is how chemists identify it in a flame test.
periodicbubbles.com/element/potassium.html
Chromium Cr · 24
The same element gives ruby its red and emerald its green: chromium atoms replacing aluminium in two different host crystals absorb light differently.
Chromium is among the hardest pure metals and takes a high polish, which is why chrome plating is used both for decoration and for wear resistance.
Chrome yellow, a lead chromate pigment, was the colour of American school buses and of several of Van Gogh's sunflower paintings, some of which have darkened as the pigment degraded.
periodicbubbles.com/element/chromium.html
Vanadium V · 23
Henry Ford used vanadium steel in the Model T from 1908 because it was much stronger than ordinary steel for the same weight.
Some sea squirts concentrate vanadium in their blood cells to levels many thousands of times higher than in seawater.
Vanadium's four common oxidation states give four distinct colours in solution: violet, green, blue and yellow, and a single reducing agent can walk a solution through all of them.
periodicbubbles.com/element/vanadium.html
Titanium Ti · 22
Klaproth named titanium after the Titans of Greek myth; he had named uranium after the planet Uranus a few years earlier.
The SR-71 Blackbird spy plane was built largely from titanium because aluminium would have softened at the temperatures reached in flight.
Titanium is one of very few metals that will burn in pure nitrogen, which is why it has to be melted under argon rather than nitrogen.
periodicbubbles.com/element/titanium.html
Cobalt Co · 27
Cobalt, isolated in 1735, was the first metal to be discovered since ancient times.
Vitamin B12 is the only vitamin that contains a metal atom, a single cobalt at its centre.
Cobalt-60 gamma sources sterilise a large share of the world's disposable medical equipment.
periodicbubbles.com/element/cobalt.html
Iron Fe · 26
The Earth's magnetic field is generated by liquid iron churning in the outer core, some 3000 kilometres beneath your feet.
Tutankhamun's dagger, found in his tomb, was made from meteoritic iron centuries before the Iron Age began in Egypt.
Mars is red because its dusty surface is rich in iron oxide, the same compound as rust.
periodicbubbles.com/element/iron.html
Manganese Mn · 25
The oxygen released by every plant, alga and cyanobacterium comes from a water-splitting cluster containing four manganese atoms in the protein called photosystem II.
The ocean floor holds vast fields of manganese nodules, which grow by only a few millimetres every million years.
Black pigments in the Lascaux cave paintings, around 17,000 years old, are manganese oxides.
periodicbubbles.com/element/manganese.html
28
Ni
Nickel
58.69344 u · Transition metal
29
Cu
Copper
63.5463 u · Transition metal
30
Zn
Zinc
65.382 u · Transition metal
31
Ga
Gallium
69.7231 u · Post-transition metal
32
Ge
Germanium
72.6308 u · Metalloid
33
As
Arsenic
74.9215956 u · Metalloid
34
Se
Selenium
78.9718 u · Polyatomic non-metal
35
Br
Bromine
79.904 u · Diatomic non-metal
36
Kr
Krypton
83.7982 u · Noble gas
Zinc Zn · 30
Zinc boils at a lower temperature than is needed to smelt its ore, so early European furnaces turned it straight into vapour that burned away in the flue.
The Zawar mines in Rajasthan were producing zinc metal in sealed retorts centuries before Europe worked out how.
American pennies minted since 1982 are 97.5 per cent zinc with a thin plating of copper.
periodicbubbles.com/element/zinc.html
Copper Cu · 29
The Statue of Liberty is clad in copper sheet, and its green colour is a protective layer of copper carbonates and sulfates that formed within a few decades of its unveiling.
Octopus and crab blood is blue because it carries oxygen with a copper protein, haemocyanin, rather than iron-based haemoglobin.
Copper kills bacteria and viruses on contact, an effect the ancient Egyptians exploited by storing water in copper vessels.
periodicbubbles.com/element/copper.html
Nickel Ni · 28
The Sudbury nickel deposits in Canada formed when a huge meteorite struck around 1.85 billion years ago, melting the crust and letting metal-rich magma pool.
The American nickel coin is 75 per cent copper and only 25 per cent nickel.
Nitinol, a nickel-titanium alloy, remembers its shape: bend it, warm it, and it springs back, which is why it is used for stents and unbreakable spectacle frames.
periodicbubbles.com/element/nickel.html
Arsenic As · 33
At normal air pressure arsenic never becomes a liquid: it goes straight from solid to vapour at about 615 °C.
Copper alloyed with arsenic was in use before tin bronze, so arsenic metallurgy is older than the Bronze Age name suggests.
The 1836 Marsh test could detect arsenic in a corpse, and it ended the era when arsenic poisoning was effectively undetectable.
periodicbubbles.com/element/arsenic.html
Germanium Ge · 32
The first working transistor, demonstrated at Bell Labs in December 1947, used a small block of germanium.
Germanium looks like a shiny metal but is transparent to infrared light, so thermal camera lenses are made from it.
Winkler discovered germanium by chasing down the seven per cent of a mineral's mass that no known element could explain.
periodicbubbles.com/element/germanium.html
Gallium Ga · 31
Gallium was the first element to be discovered after Mendeleev's periodic table had predicted it, including a good estimate of its density.
Like water, gallium expands as it freezes, so a sealed glass bottle of liquid gallium can crack in a cold room.
A single drop of gallium placed on an aluminium drinks can will make the aluminium brittle enough to crumble within hours.
periodicbubbles.com/element/gallium.html
Krypton Kr · 36
From 1960 to 1983 the metre was officially defined as a fixed number of wavelengths of orange-red light emitted by krypton-86 atoms.
Krypton was discovered in May 1898, and the same two scientists found neon within weeks and xenon a few weeks after that.
Krypton fluoride lasers, glowing in deep ultraviolet, printed the circuits of many generations of computer chips.
periodicbubbles.com/element/krypton.html
Bromine Br · 35
Bromine and mercury are the only two elements that are liquid at normal room temperature and pressure.
Balard was 23 years old when he identified bromine in salt marsh brine.
Bromine's two stable isotopes are so evenly split that its atomic mass comes out almost exactly at 80.
periodicbubbles.com/element/bromine.html
Selenium Se · 34
Selenium was discovered in the red sludge that built up in a sulfuric acid factory part-owned by Berzelius.
Grey selenium conducts electricity far better in light than in the dark, which is why it coated the drums of the first photocopiers.
Brazil nuts are the richest common food source of selenium, and a single nut can contain more than an adult needs in a day.
periodicbubbles.com/element/selenium.html
37
Rb
Rubidium
85.46783 u · Alkali metal
38
Sr
Strontium
87.621 u · Alkaline earth metal
39
Y
Yttrium
88.905842 u · Transition metal
40
Zr
Zirconium
91.2242 u · Transition metal
41
Nb
Niobium
92.906372 u · Transition metal
42
Mo
Molybdenum
95.951 u · Transition metal
43
Tc
Technetium
98 u · Transition metal
44
Ru
Ruthenium
101.072 u · Transition metal
45
Rh
Rhodium
102.905502 u · Transition metal
Yttrium Y · 39
The quarry at Ytterby, Sweden, is the source of four element names: yttrium, ytterbium, terbium and erbium.
Nearly every white LED contains yttrium in the yellow phosphor that turns blue light into white.
Yttrium barium copper oxide, discovered in 1987, was the first superconductor to work above the boiling point of liquid nitrogen.
periodicbubbles.com/element/yttrium.html
Strontium Sr · 38
Strontium is the only element named after a place in the United Kingdom: Strontian, a village in the Scottish Highlands.
A survey of baby teeth in St Louis found strontium-90 from nuclear tests rising year by year, which helped bring about the 1963 Partial Test Ban Treaty.
The glow-in-the-dark stars on bedroom ceilings are usually strontium aluminate, which replaced radioactive radium paint.
periodicbubbles.com/element/strontium.html
Rubidium Rb · 37
Rubidium-87 has a half-life of about 49 billion years, more than three times the current age of the universe.
The first Bose-Einstein condensate, a cloud of atoms cooled to within a whisker of absolute zero, was made from rubidium-87 in 1995.
Every GPS satellite in orbit carries rubidium atomic clocks to keep its timing signals accurate.
periodicbubbles.com/element/rubidium.html
Molybdenum Mo · 42
Molybdenum is the most abundant transition metal dissolved in the oceans, which is why marine microbes evolved to depend on it.
The enzyme nitrogenase, which lets bacteria turn nitrogen gas into ammonia, has molybdenum at its heart, and most of the protein on Earth passes through it.
Only a handful of elements melt at a higher temperature than molybdenum's 2623 °C.
periodicbubbles.com/element/molybdenum.html
Niobium Nb · 41
Brazil supplies roughly nine tenths of the world's niobium, most of it from one deposit at Araxá.
Niobium becomes a superconductor below about 9.2 kelvin, the highest transition temperature of any pure element at normal pressure.
Niobe was the daughter of Tantalus in Greek myth, and the element was named to reflect how inseparable it is from tantalum.
periodicbubbles.com/element/niobium.html
Zirconium Zr · 40
Zircon crystals from the Jack Hills in Western Australia are about 4.4 billion years old, the oldest known pieces of the Earth's crust.
The hydrogen explosions at Fukushima in 2011 came from overheated zirconium fuel cladding reacting with steam.
Cubic zirconia is a synthetic crystal of zirconium dioxide; the natural gemstone zircon is a different mineral, zirconium silicate.
periodicbubbles.com/element/zirconium.html
Rhodium Rh · 45
Rhodium is usually the most expensive metal traded on world markets, and in 2021 its price rose above ten times that of gold.
In 1979 the Guinness Book of Records presented Paul McCartney with a rhodium-plated disc as the most successful songwriter of all time.
William Hyde Wollaston discovered rhodium and palladium within about a year of each other from the same batch of crude platinum.
periodicbubbles.com/element/rhodium.html
Ruthenium Ru · 44
Most hard disk drives made since the mid-2000s contain a ruthenium layer just a few atoms thick beneath the magnetic recording film.
Ruthenium is one of the very few elements that can reach the +8 oxidation state, alongside osmium and xenon.
The anodes that produce most of the world's chlorine are coated with ruthenium oxide.
periodicbubbles.com/element/ruthenium.html
Technetium Tc · 43
Technetium was the first element produced artificially, identified in 1937 in a discarded piece of cyclotron equipment posted from California to Sicily.
In 1952 technetium was detected in the light of red giant stars, proving that stars are still manufacturing heavy elements today.
Technetium-99m is used in most diagnostic nuclear medicine scans worldwide, amounting to tens of millions of procedures a year.
periodicbubbles.com/element/technetium.html
46
Pd
Palladium
106.421 u · Transition metal
47
Ag
Silver
107.86822 u · Transition metal
48
Cd
Cadmium
112.4144 u · Transition metal
49
In
Indium
114.8181 u · Post-transition metal
50
Sn
Tin
118.7107 u · Post-transition metal
51
Sb
Antimony
121.7601 u · Metalloid
52
Te
Tellurium
127.603 u · Metalloid
53
I
Iodine
126.904473 u · Diatomic non-metal
54
Xe
Xenon
131.2936 u · Noble gas
Cadmium Cd · 48
Cadmium was discovered in 1817 as an unwanted yellow tint in zinc oxide sold by German pharmacies.
The bright yellows in many Impressionist paintings come from cadmium sulfide, which became available as an artists' pigment in the mid nineteenth century.
Cadmium boils at about 767 °C, well below the temperature at which copper melts, which is unusual for a metal.
periodicbubbles.com/element/cadmium.html
Silver Ag · 47
Silver tarnishes not because of oxygen but because of tiny amounts of hydrogen sulfide in the air, which form a dark layer of silver sulfide.
Polished silver reflects more visible light than any other metal, which is why it was used to back the earliest glass mirrors.
Silver iodide crystals are seeded into clouds to encourage rain or snow, because their structure resembles that of ice.
periodicbubbles.com/element/silver.html
Palladium Pd · 46
Palladium can absorb several hundred times its own volume of hydrogen gas, swelling slightly as the hydrogen atoms slip between the metal atoms.
Wollaston kept his discovery anonymous at first and sold the new metal through a Soho shop, prompting a rival chemist to call it a fake.
Palladium is named after the asteroid Pallas, which in turn is named after the Greek goddess Pallas Athena.
periodicbubbles.com/element/palladium.html
Antimony Sb · 51
Stibnite, antimony's main ore, was ground up and used as kohl eye make-up in ancient Egypt.
Antimony is one of the few substances that expands when it freezes, a property shared with water, bismuth and gallium.
The Xikuangshan mine in Hunan, China, has for over a century been the largest antimony source on Earth.
periodicbubbles.com/element/antimony.html
Tin Sn · 50
A bar of pure tin makes a crackling sound when bent, called tin cry, as its crystal structure deforms.
Below about 13 °C, white metallic tin slowly transforms into a brittle grey powder, a change known as tin pest that can crumble old pewter and tin objects.
Tin has ten stable isotopes, more than any other element.
periodicbubbles.com/element/tin.html
Indium In · 49
Indium is soft enough to be scratched with a fingernail and, like tin, gives a faint crackling sound when bent as its crystals shift.
Ferdinand Reich, who first isolated indium compounds, was colour-blind and had to ask a colleague to identify the element's indigo spectral line.
A drop of molten indium wets clean glass and sticks to it, which makes it useful for sealing glass to metal in scientific instruments.
periodicbubbles.com/element/indium.html
Xenon Xe · 54
Xenon was the first noble gas to form a chemical compound, when Neil Bartlett made xenon hexafluoroplatinate in 1962.
Xenon is so dense that a person who inhales it briefly speaks with a much deeper voice, the opposite of the helium effect.
NASA's Dawn spacecraft used xenon ion thrusters to orbit two different bodies in the asteroid belt, the first mission ever to do so.
periodicbubbles.com/element/xenon.html
Iodine I · 53
Iodine was discovered by accident when a gunpowder manufacturer added too much acid to seaweed ash and saw violet vapour rise.
The thyroid hormone thyroxine contains four iodine atoms per molecule, which is why it is abbreviated T4.
A drop of iodine solution turns starch an intense blue-black, a test still used in school laboratories.
periodicbubbles.com/element/iodine.html
Tellurium Te · 52
Exposure to a tiny amount of tellurium gives a person garlic-smelling breath that can persist for weeks.
Tellurium is roughly as rare in the Earth's crust as platinum, but far more common in the universe as a whole.
During the Kalgoorlie gold rush in Australia, miners discarded a grey mineral as waste before realising it was calaverite, a gold telluride rich in gold.
periodicbubbles.com/element/tellurium.html
55
Cs
Cesium
132.905451966 u · Alkali metal
56
Ba
Barium
137.3277 u · Alkaline earth metal
57
La
Lanthanum
138.905477 u · Lanthanide
58
Ce
Cerium
140.1161 u · Lanthanide
59
Pr
Praseodymium
140.907662 u · Lanthanide
60
Nd
Neodymium
144.2423 u · Lanthanide
61
Pm
Promethium
145 u · Lanthanide
62
Sm
Samarium
150.362 u · Lanthanide
63
Eu
Europium
151.9641 u · Lanthanide
Lanthanum La · 57
Lanthanum means hidden, because it lay undetected inside cerium compounds for more than thirty years.
Lanthanum is more abundant in the Earth's crust than lead, despite being called a rare earth.
Early hybrid cars carried battery packs containing several kilograms of lanthanum in their nickel-metal hydride cells.
periodicbubbles.com/element/lanthanum.html
Barium Ba · 56
The Bologna stone, a barite mineral that glowed after exposure to sunlight, was one of the first known phosphorescent materials, described in the early seventeenth century.
Barium's name means heavy, yet the metal is less than half as dense as iron.
The green colour in fireworks almost always comes from barium compounds.
periodicbubbles.com/element/barium.html
Cesium Cs · 55
The second is defined as exactly 9,192,631,770 oscillations of the microwave radiation that flips caesium-133 atoms between two energy states.
Caesium was the first element discovered using a spectroscope, and it was named after the sky-blue lines it produces.
Bunsen and Kirchhoff boiled down tens of thousands of litres of mineral water to obtain just a few grams of caesium salts.
periodicbubbles.com/element/cesium.html
Neodymium Nd · 60
Neodymium-iron-boron magnets, invented in 1984, are the strongest type of permanent magnet commercially available.
A single large wind turbine generator can contain several hundred kilograms of neodymium in its magnets.
Neodymium glass appears lilac in daylight but bluish under fluorescent lighting, because the ions absorb a narrow band of yellow light.
periodicbubbles.com/element/neodymium.html
Praseodymium Pr · 59
Praseodymium's name means leek-green twin, describing the colour of its salts and its long confusion with neodymium.
Didymium was listed as an element for over forty years before being shown to be a mixture of praseodymium and neodymium.
Glassblowers' safety glasses often contain praseodymium and neodymium, which filter out the glare of hot sodium.
periodicbubbles.com/element/praseodymium.html
Cerium Ce · 58
Cerium is about as common in the Earth's crust as copper, making it the most abundant of the rare earth elements.
Cerium was named after Ceres, which was discovered in 1801 and is now classed as a dwarf planet.
The spark from a cigarette lighter comes from a cerium-rich alloy called mischmetal that ignites when scraped.
periodicbubbles.com/element/cerium.html
Europium Eu · 63
Europium is soft enough to be dented with a fingernail and is the least dense of all the lanthanide metals.
The bright red in early colour televisions came from a europium phosphor, and modern white LEDs still rely on europium to tune their colour.
Rocks from the Moon's highlands contain unusually high levels of europium because europium(II) mimics calcium and slots into feldspar minerals.
periodicbubbles.com/element/europium.html
Samarium Sm · 62
Samarium-147 decays so slowly, with a half-life around a hundred billion years, that geologists use it to date some of the oldest rocks on Earth and meteorites from the early solar system.
Samarium cobalt magnets keep their strength at temperatures where neodymium magnets lose theirs, which is why they are used in jet engines and satellites.
The element is named after the mineral samarskite, which honours a Russian mining official, making samarium the first element named, indirectly, after a person.
periodicbubbles.com/element/samarium.html
Promethium Pm · 61
Promethium is the only lanthanide with no stable isotope, and one of just two elements lighter than bismuth without one (technetium is the other).
Its salts glow faintly in the dark with a pale blue or green light, caused by their own radioactivity exciting the surrounding material.
The table gives its atomic mass as a whole number, 145, because there is no natural isotope mixture from which to calculate a standard atomic weight.
periodicbubbles.com/element/promethium.html
64
Gd
Gadolinium
157.253 u · Lanthanide
65
Tb
Terbium
158.925352 u · Lanthanide
66
Dy
Dysprosium
162.5001 u · Lanthanide
67
Ho
Holmium
164.930332 u · Lanthanide
68
Er
Erbium
167.2593 u · Lanthanide
69
Tm
Thulium
168.934222 u · Lanthanide
70
Yb
Ytterbium
173.0451 u · Lanthanide
71
Lu
Lutetium
174.96681 u · Lanthanide
72
Hf
Hafnium
178.492 u · Transition metal
Dysprosium Dy · 66
Dysprosium's name means hard to get at in Greek, chosen after its discoverer needed more than thirty rounds of purification to isolate it.
Adding a small amount of dysprosium lets neodymium magnets keep working at the high temperatures inside electric car motors and wind turbine generators.
Together with holmium, dysprosium has one of the strongest magnetic moments of any element.
periodicbubbles.com/element/dysprosium.html
Terbium Tb · 65
Terbium is one of four elements named after the village of Ytterby in Sweden, along with yttrium, erbium and ytterbium.
The names terbia and erbia were swapped by later chemists, so the substance Mosander called erbia is the one we now call terbium oxide.
Terfenol-D, an alloy of terbium, dysprosium and iron, physically stretches in a magnetic field and can turn a window or desk into a loudspeaker.
periodicbubbles.com/element/terbium.html
Gadolinium Gd · 64
Gadolinium becomes ferromagnetic below about 20 °C, so it will stick to a magnet on a cold day but not on a warm one.
Gadolinium-157 has the highest thermal neutron capture cross-section of any known stable isotope, which is why it is used to shut reactors down.
Gadolinium atoms have seven unpaired electrons, more than any other element, giving them exceptionally strong magnetic moments.
periodicbubbles.com/element/gadolinium.html
Thulium Tm · 69
Thulium is the least abundant of the rare earths that have stable isotopes, yet it is still more plentiful in the crust than silver, gold or platinum.
Its name comes from Thule, the name ancient Greek and Roman writers gave to the northernmost land they knew of.
Thulium-170, made by irradiating natural thulium in a reactor, powers compact X-ray sources that need no electricity.
periodicbubbles.com/element/thulium.html
Erbium Er · 68
Erbium doped fibre amplifiers boost the light signals in nearly every long distance and undersea internet cable, operating at a wavelength where glass is most transparent.
Erbium oxide is pink and has been used to colour glass, ceramic glazes and cubic zirconia gemstones.
The names erbia and terbia were swapped by chemists after Mosander first proposed them in 1843.
periodicbubbles.com/element/erbium.html
Holmium Ho · 67
Holmium has the highest magnetic moment of any naturally occurring element, though the metal itself is only ferromagnetic when cooled far below room temperature.
Holmium lasers are the standard tool for breaking kidney stones because their 2.1 micrometre light is absorbed almost instantly by water.
Holmium was discovered twice in quick succession, first as Element X by Delafontaine and Soret in 1878, then by Cleve in 1879, who named it after Stockholm.
periodicbubbles.com/element/holmium.html
Hafnium Hf · 72
Hafnium atoms are almost exactly the same size as zirconium atoms, which is why the two elements went unseparated for over a century.
The discovery in 1923 confirmed Niels Bohr's prediction that element 72 would be a transition metal rather than a rare earth.
Hafnium oxide replaced silicon dioxide as the insulating layer in advanced microprocessors from 2007 onwards, allowing transistors to keep shrinking.
periodicbubbles.com/element/hafnium.html
Lutetium Lu · 71
Lutetium is the densest, hardest and highest melting of all the lanthanides, a direct result of having the smallest atoms in the series.
Lutetium-177 based drugs bind to prostate cancer and neuroendocrine tumour cells and irradiate them from inside the body.
The element was discovered independently by three chemists in 1907, and the German name cassiopeium remained in use for decades.
periodicbubbles.com/element/lutetium.html
Ytterbium Yb · 70
Ytterbium optical lattice clocks are more accurate than the caesium clocks that currently define the second and may help redefine it.
Ytterbium has the lowest boiling point of all the lanthanides, at roughly 1196 °C, which is exploited to purify it by distillation.
Ytterbium doped fibre lasers cut and weld metal in factories worldwide, delivering kilowatts of power through a flexible glass fibre.
periodicbubbles.com/element/ytterbium.html
73
Ta
Tantalum
180.947882 u · Transition metal
74
W
Tungsten
183.841 u · Transition metal
75
Re
Rhenium
186.2071 u · Transition metal
76
Os
Osmium
190.233 u · Transition metal
77
Ir
Iridium
192.2173 u · Transition metal
78
Pt
Platinum
195.0849 u · Transition metal
79
Au
Gold
196.9665695 u · Transition metal
80
Hg
Mercury
200.5923 u · Transition metal
81
Tl
Thallium
204.38 u · Post-transition metal
Rhenium Re · 75
Rhenium was the last element with a stable isotope to be discovered, in 1925; every element found since has been radioactive.
There are no rhenium mines. All of it is recovered from the exhaust gases of plants roasting molybdenum ore.
Rhenium has the highest boiling point of any element by most measurements, and only tungsten and carbon melt at higher temperatures.
periodicbubbles.com/element/rhenium.html
Tungsten W · 74
Tungsten has the highest melting point of any metal, at about 3422 °C, which is why it served as the filament in light bulbs for a century.
Tungsten is almost exactly as dense as gold, and gold plated tungsten bars have been used in attempts to counterfeit bullion.
The symbol W comes from wolfram, the name still used in German, after a mineral that medieval tin miners said devoured tin like a wolf.
periodicbubbles.com/element/tungsten.html
Tantalum Ta · 73
Tantalum is named after Tantalus, who was punished with unquenchable thirst, because its oxide would not absorb acid.
Niobium was named after Niobe, the daughter of Tantalus, because the two metals were so hard to tell apart.
Tantalum capacitors in phones and laptops pack a large charge into a tiny space thanks to an oxide layer only nanometres thick.
periodicbubbles.com/element/tantalum.html
Platinum Pt · 78
Platinum is mined at only a fraction of the rate of gold; world mine output is a couple of hundred tonnes a year, compared with several thousand tonnes of gold.
The anti-cancer drug cisplatin was discovered by accident in the 1960s when bacteria near platinum electrodes stopped dividing.
Pre-Columbian metalworkers in South America shaped platinum by binding its grains with gold, centuries before any European furnace could melt it.
periodicbubbles.com/element/platinum.html
Iridium Ir · 77
The worldwide iridium-rich clay layer, identified by Luis and Walter Alvarez and colleagues in 1980, is key evidence for the asteroid impact linked to the extinction of the dinosaurs.
A cylinder of platinum-iridium alloy kept near Paris defined the kilogram from 1889 until 2019.
Iridium is not attacked by any single acid or by aqua regia at room temperature, making it the most corrosion resistant metal known.
periodicbubbles.com/element/iridium.html
Osmium Os · 76
Osmium and iridium are so close in density, 22.59 and 22.56 grams per cubic centimetre, that for much of the twentieth century scientists disagreed about which was heavier.
The lighting company Osram takes its name from osmium and wolfram, the German word for tungsten, the two metals used in early light bulb filaments.
Osmium tetroxide is used to stain cell membranes so they show up clearly under an electron microscope.
periodicbubbles.com/element/osmium.html
Thallium Tl · 81
Thallium poisoning was famously used in Agatha Christie's novel The Pale Horse, and in the 1970s a real case in London was diagnosed after a nurse recognised the symptoms from the book.
The antidote to thallium poisoning is Prussian blue, the same pigment artists have used since the eighteenth century.
Thallium's name means green twig, after the bright green line it produces in a flame spectrum.
periodicbubbles.com/element/thallium.html
Mercury Hg · 80
Mercury is so dense that iron, lead and even a cannonball will float on it.
The chemical symbol Hg comes from the Latin hydrargyrum, meaning water-silver.
The phrase mad as a hatter is linked to mercury poisoning among workers who used mercury compounds to make felt hats.
periodicbubbles.com/element/mercury.html
Gold Au · 79
All the gold ever mined, well over 200,000 tonnes, would fit in a cube roughly 22 metres on each side.
Gold is so malleable that a single gram can be beaten into a sheet about a square metre in area, and gold leaf is thin enough for greenish light to pass through it.
Gold's yellow colour is a relativistic effect: its electrons move so fast that the energy levels shift and blue light is absorbed.
periodicbubbles.com/element/gold.html
82
Pb
Lead
207.21 u · Post-transition metal
83
Bi
Bismuth
208.980401 u · Post-transition metal
84
Po
Polonium
209 u · Post-transition metal
85
At
Astatine
210 u · Metalloid
86
Rn
Radon
222 u · Noble gas
87
Fr
Francium
223 u · Alkali metal
88
Ra
Radium
226 u · Alkaline earth metal
89
Ac
Actinium
227 u · Actinide
90
Th
Thorium
232.03774 u · Actinide
Polonium Po · 84
Polonium was the first element discovered by detecting its radioactivity, and the first named to draw attention to a political cause.
A gram of polonium-210 releases about 140 watts of heat and can warm itself until it glows.
Polonium is the only element whose stable room temperature form has a simple cubic crystal structure.
periodicbubbles.com/element/polonium.html
Bismuth Bi · 83
Bismuth-209 was long thought to be stable, but in 2003 physicists measured its half-life at about 20 billion billion years, more than a billion times the age of the universe.
The rainbow colours on bismuth crystals come from a thin oxide film that makes different wavelengths of light interfere, the same effect as a soap bubble.
Bismuth expands by about three per cent as it solidifies, one of very few substances besides water to do so.
periodicbubbles.com/element/bismuth.html
Lead Pb · 82
Lead pollution from Roman smelters can be measured in Greenland ice cores laid down two thousand years ago.
The lead in pencils has never been lead; it is graphite, mistaken for a lead ore when it was first mined in Cumbria.
Lead-208 is the heaviest atomic nucleus that is considered completely stable, and three of lead's isotopes are the end products of uranium and thorium decay.
periodicbubbles.com/element/lead.html
Francium Fr · 87
Marguerite Perey joined the Radium Institute at nineteen as Marie Curie's personal laboratory assistant and discovered francium ten years later.
The total amount of francium in the Earth's crust at any moment is estimated at only 20 to 30 grams.
Francium was the last element discovered in nature; every element found after 1939 was first made artificially.
periodicbubbles.com/element/francium.html
Radon Rn · 86
Radon is the densest gas among the elements, about eight times heavier than air.
For the average person in the UK, radon accounts for roughly half of all the radiation dose they receive in a year.
In the early 1900s radon was marketed as a health cure, sold in drinking water and offered in spa treatments.
periodicbubbles.com/element/radon.html
Astatine At · 85
The total amount of astatine in the Earth's crust at any moment is estimated at less than about 30 grams.
Astatine's name comes from the Greek word for unstable; its most durable isotope lasts just eight hours before half of it has decayed.
A visible lump of astatine has never existed, because its own radioactivity would heat it until it vaporised.
periodicbubbles.com/element/astatine.html
Thorium Th · 90
Thorium-232 has a half-life of about 14 billion years, roughly the age of the universe, so around 80 per cent of the thorium present when the Earth formed is still here.
The decay of thorium, uranium and potassium in the Earth's interior produces a large share of the heat that drives plate tectonics and volcanoes.
Thorium and vanadium are the only two elements named after Norse deities; vanadium honours Vanadis, a name for the goddess Freyja.
periodicbubbles.com/element/thorium.html
Actinium Ac · 89
Actinium glows pale blue in the dark because its radiation ionises the surrounding air.
The actinide series is named after actinium, yet actinium itself has no electrons in the 5f orbitals that define the series.
Actinium is roughly 150 times more radioactive than radium.
periodicbubbles.com/element/actinium.html
Radium Ra · 88
The paint on old radium watch dials has stopped glowing not because the radium is gone, only about five per cent has decayed in a century, but because the zinc sulfide phosphor has been worn out by the radiation.
Marie Curie's laboratory notebooks are still radioactive and are stored in lead lined boxes; readers must sign a waiver to handle them.
In the 1920s radium sold for more than 100,000 US dollars a gram, making it the most expensive substance in the world.
periodicbubbles.com/element/radium.html
91
Pa
Protactinium
231.035882 u · Actinide
92
U
Uranium
238.028913 u · Actinide
93
Np
Neptunium
237 u · Actinide
94
Pu
Plutonium
244 u · Actinide
95
Am
Americium
243 u · Actinide
96
Cm
Curium
247 u · Actinide
97
Bk
Berkelium
247 u · Actinide
98
Cf
Californium
251 u · Actinide
99
Es
Einsteinium
252 u · Actinide
Neptunium Np · 93
Neptunium-239, the isotope found in 1940, lasts just over two days before turning into plutonium-239; it is the route by which all reactor plutonium is made.
The mistaken belief in the 1930s that element 93 had already been found helped delay the discovery of fission, because chemists were looking for heavy elements instead of split nuclei.
Neptunium has been detected in tiny quantities in uranium ore, formed by natural neutron capture.
periodicbubbles.com/element/neptunium.html
Uranium U · 92
Uranium-238 has a half-life of about 4.5 billion years, almost exactly the age of the Earth, so roughly half the uranium the planet started with is still here.
Uranium glass, popular from the 1830s to the 1940s, fluoresces bright green under ultraviolet light, and collectors still hunt for it at car boot sales.
Seawater contains about three micrograms of uranium per litre, and the oceans hold far more uranium in total than all known land deposits.
periodicbubbles.com/element/uranium.html
Protactinium Pa · 91
The 125 gram batch purified in the UK in 1961 came from about 60 tonnes of uranium processing residue, an extraction ratio of roughly one part in half a million.
The first protactinium isotope ever isolated, found by Crookes in 1900, lives for only a little over a minute, which is why the element was once called brevium.
The name was shortened from protoactinium to protactinium in 1949, more than thirty years after the element was named.
periodicbubbles.com/element/protactinium.html
Curium Cm · 96
Curium glows purple in the dark because its intense alpha radiation excites the surrounding air and its own surface.
Curium-244 produces roughly 2.8 watts of heat per gram, several times more than plutonium-238.
The instrument that identified elements in Martian rocks on four NASA rovers used a curium alpha source.
periodicbubbles.com/element/curium.html
Americium Am · 95
A typical household smoke detector contains about 0.3 micrograms of americium-241, with an activity of roughly 37 kilobecquerels.
Americium went on sale to industry from the US Atomic Energy Commission in 1962, at 1,500 dollars per gram.
The discovery team nicknamed americium pandemonium because it was so hard to separate from curium, which they called delirium.
periodicbubbles.com/element/americium.html
Plutonium Pu · 94
Plutonium's delta phase contracts as it is heated, one of very few metals with negative thermal expansion.
Plutonium is warm to the touch, and a sizeable piece of plutonium-238 can glow red from its own decay heat.
The Voyager probes, launched in 1977, still send data from interstellar space using electricity from plutonium-238 decay.
periodicbubbles.com/element/plutonium.html
Einsteinium Es · 99
Einsteinium was first detected in fallout collected on filter papers by aircraft flying through the cloud of the Ivy Mike test.
Uranium atoms in the bomb absorbed at least fifteen neutrons each in a fraction of a second to produce einsteinium.
The 2021 bond-length experiment used about 200 nanograms of einsteinium-254, a tiny fraction of the mass of a grain of salt.
periodicbubbles.com/element/einsteinium.html
Californium Cf · 98
A single microgram of californium-252 emits over two million neutrons every second.
Californium-252 sources have been used to search for landmines and explosives, because neutrons make hidden nitrogen-rich compounds give off telltale gamma rays.
Oganesson, the heaviest element ever made, was first produced by bombarding a californium-249 target with calcium ions at Dubna in 2002.
periodicbubbles.com/element/californium.html
Berkelium Bk · 97
The total amount of berkelium ever made is around a gram, spread over more than seventy years of production.
The 22-milligram target used to discover tennessine took about 250 days of reactor irradiation and 90 days of chemical purification to prepare.
Berkelium-249 turns into californium-249 with a half-life of 330 days, so a sample is noticeably different after a year on the shelf.
periodicbubbles.com/element/berkelium.html
100
Fm
Fermium
257 u · Actinide
101
Md
Mendelevium
258 u · Actinide
102
No
Nobelium
259 u · Actinide
103
Lr
Lawrencium
266 u · Actinide
104
Rf
Rutherfordium
267 u · Transition metal
105
Db
Dubnium
268 u · Transition metal
106
Sg
Seaborgium
269 u · Transition metal
107
Bh
Bohrium
270 u · Transition metal
108
Hs
Hassium
269 u · Transition metal
Nobelium No · 102
Nobelium is the only actinide whose most stable form in water is the +2 ion, behaving like a very heavy calcium.
The 1957 Swedish claim gave the element its name, even though the discovery itself was later rejected.
In 2016 nobelium became the heaviest element to have its atomic spectrum measured with lasers, at the GSI laboratory in Germany.
periodicbubbles.com/element/nobelium.html
Mendelevium Md · 101
The discovery relied on just seventeen atoms, recorded one at a time as spontaneous fission events.
The einsteinium target contained about a billion atoms, too few to be visible and weighing far less than a nanogram.
A bell was wired to the detector so that the team would hear each mendelevium atom as it decayed.
periodicbubbles.com/element/mendelevium.html
Fermium Fm · 100
Fermium-258 undergoes spontaneous fission with a half-life of less than a thousandth of a second, which blocks reactors from making anything heavier than fermium.
About 200 atoms of fermium were enough to establish its discovery in 1953.
Fermium has never been seen as a solid; everything known about it comes from atoms in solution.
periodicbubbles.com/element/fermium.html
Dubnium Db · 105
Dubnium-268 has a half-life of roughly a day, which is long enough for chemists to dissolve it and study it in solution, a rare luxury among superheavy elements.
The unofficial name hahnium appeared in American textbooks for over twenty years, was then proposed for element 108 instead, and was finally dropped altogether.
In 1997 IUPAC settled the disputed names of elements 104 to 109 in a single decision, ending the so-called Transfermium Wars.
periodicbubbles.com/element/dubnium.html
Rutherfordium Rf · 104
Rutherfordium was called kurchatovium in Soviet and some other publications for almost thirty years before IUPAC settled on rutherfordium in 1997.
If its predicted density of about 23 grams per cubic centimetre is correct, a golf-ball-sized piece would weigh close to a kilogram.
Chemistry experiments on rutherfordium are done with isotopes that live about a minute, using gas streams to move atoms from the target to detectors.
periodicbubbles.com/element/rutherfordium.html
Lawrencium Lr · 103
Lawrencium's first ionisation energy was measured in 2015 using atoms produced a few at a time, one of the most delicate measurements in chemistry.
Its longest-lived isotope, lawrencium-266, was found only in 2014, far down the decay chain of tennessine.
The symbol was Lw for two years before IUPAC changed it to Lr in 1963.
periodicbubbles.com/element/lawrencium.html
Hassium Hs · 108
Hassium tetroxide, made in 2001 from a handful of atoms, is the heaviest oxide ever detected.
Predicted at around 41 grams per cubic centimetre, hassium would be nearly twice as dense as osmium and iridium, the densest elements ever weighed.
Hassium-270 has 162 neutrons, a number nuclear physicists expect to give extra stability to slightly squashed, deformed nuclei.
periodicbubbles.com/element/hassium.html
Bohrium Bh · 107
Only five atoms of bohrium were detected in the 1981 discovery experiment, and that was enough to satisfy the international review.
The chemistry of bohrium was first studied in 2000 using a total of six atoms, which formed a compound with oxygen and chlorine.
Niels Bohr won the Nobel Prize in Physics in 1922. His son Aage Bohr won the same prize in 1975 for work on the structure of the nucleus.
periodicbubbles.com/element/bohrium.html
Seaborgium Sg · 106
Glenn Seaborg liked to point out that a letter could reach him using only element names: seaborgium, lawrencium (for his laboratory), berkelium, californium, americium.
In 2014 researchers made seaborgium hexacarbonyl, a molecule with one seaborgium atom surrounded by six carbon monoxide groups, using only a few dozen atoms.
IUPAC's 1994 proposal would have called element 106 rutherfordium and element 104 dubnium. Both suggestions were overturned in 1997.
periodicbubbles.com/element/seaborgium.html
109
Mt
Meitnerium
278 u · Unknown, probably transition metal
110
Ds
Darmstadtium
281 u · Unknown, probably transition metal
111
Rg
Roentgenium
282 u · Unknown, probably transition metal
112
Cn
Copernicium
285 u · Transition metal
113
Nh
Nihonium
286 u · Unknown, probably transition metal
114
Fl
Flerovium
289 u · Post-transition metal
115
Mc
Moscovium
289 u · Unknown, probably post-transition metal
116
Lv
Livermorium
293 u · Unknown, probably post-transition metal
117
Ts
Tennessine
294 u · Unknown, probably metalloid
Roentgenium Rg · 111
Wilhelm Rontgen refused to patent X-rays, saying discoveries belonged to humanity, and gave his Nobel Prize money to the University of Wurzburg.
The 1994 discovery rested on just three atoms of roentgenium-272, each lasting a few milliseconds.
Roentgenium is predicted to be about 50 per cent denser than gold, the element directly above it.
periodicbubbles.com/element/roentgenium.html
Darmstadtium Ds · 110
The number 110 is the emergency telephone number for the police in Germany, which led to the joking suggestion of the name policium.
The GSI team considered naming the element wixhausium after Wixhausen, the district of Darmstadt where the laboratory is located.
The first darmstadtium atom was detected on 9 November 1994, five years to the day after the fall of the Berlin Wall.
periodicbubbles.com/element/darmstadtium.html
Meitnerium Mt · 109
The 1982 discovery rested on a single atom, identified by the chain of alpha decays it produced in the detector.
Lise Meitner was nominated for a Nobel Prize dozens of times in both physics and chemistry but never received one.
Meitner became the first woman in Germany to hold the title of full professor of physics, at the University of Berlin in 1926.
periodicbubbles.com/element/meitnerium.html
Flerovium Fl · 114
Calcium-48, the beam used to make flerovium, is less than 0.2 per cent of natural calcium and costs a great deal to enrich.
Georgy Flyorov's 1942 letter to Stalin pointing out the sudden silence in Western fission research helped launch the Soviet atomic programme.
The hypothetical isotope flerovium-298, with 184 neutrons, is the predicted heart of the island of stability, but no known reaction can reach it.
periodicbubbles.com/element/flerovium.html
Nihonium Nh · 113
RIKEN detected just three atoms of nihonium-278 in total: one in 2004, one in 2005 and one in 2012.
The bismuth-209 target used to make nihonium is itself very faintly radioactive, with a half-life about a billion times the current age of the universe.
In 1908 the Japanese chemist Masataka Ogawa claimed a new element he named nipponium; it was later concluded he had probably found rhenium, which was not officially discovered until 1925.
periodicbubbles.com/element/nihonium.html
Copernicium Cn · 112
The name copernicium was made official on 19 February 2010, the anniversary of Copernicus's birth in 1473.
The original symbol Cp was rejected because chemists already used it for the cyclopentadienyl group and it had once stood for cassiopeium, an old name for lutetium.
Only one atom was detected in the 1996 discovery experiment and one more when it was repeated in 2000.
periodicbubbles.com/element/copernicium.html
Tennessine Ts · 117
Tennessine is the most recently discovered element, first made in 2010, later than oganesson, nihonium and the rest of period 7.
The berkelium-249 target, about 22 milligrams, took roughly 250 days of reactor irradiation at Oak Ridge to produce and had a half-life of only 330 days.
The shipment of berkelium to Russia was twice refused by customs over paperwork and crossed the Atlantic several times before it arrived.
periodicbubbles.com/element/tennessine.html
Livermorium Lv · 116
A 1999 claim to have discovered elements 116 and 118 at Berkeley was retracted after the laboratory concluded that data had been fabricated.
The Dubna and Livermore collaboration has been credited with five elements: flerovium, moscovium, livermorium, tennessine and oganesson.
The city of Livermore, and hence the element, takes its name from Robert Livermore, an English sailor who became a Californian rancher in the 1800s.
periodicbubbles.com/element/livermorium.html
Moscovium Mc · 115
In 1989 Bob Lazar claimed a stable element 115 fuelled alien craft; the real moscovium decays in a fraction of a second.
A single moscovium-288 atom decays through five other elements before reaching dubnium-268, giving physicists five isotopes from one event.
The 2003 discovery was strengthened by performing chemistry on the dubnium at the end of the decay chain, the first time chemistry helped confirm a superheavy element.
periodicbubbles.com/element/moscovium.html
118
Og
Oganesson
294 u · Unknown, predicted to be noble gas
Oganesson Og · 118
Only about five atoms of oganesson have ever been detected, making it the rarest element that has ever existed.
Yuri Oganessian is only the second person, after Glenn Seaborg, to have an element named after him while alive.
Oganesson is predicted to be a solid at room temperature, unlike every other noble gas, with a boiling point around 77 degrees Celsius.
periodicbubbles.com/element/oganesson.html
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