Iron vs Copper
Both are transition metals, so they share the same broad chemistry.
The differences in plain English
- They share period 4, the same row, so their outer electrons are in the same shell but they differ in how many there are: Iron has 2, Copper has 1.
- Both are solids at room temperature.
- Copper is denser, only slightly more than Iron (8.96 against 7.874 g/cm³).
- Iron melts at 1538 °C, far above Copper at 1085 °C.
- An atom of Copper is only slightly heavier than an atom of Iron (63.55 u against 55.85 u).
- Copper pulls electrons more strongly in a bond (electronegativity 1.9 against 1.83).
Side by side
| Iron | Copper | |
|---|---|---|
| Atomic number | 26 | 29 |
| Symbol | Fe | Cu |
| Family | Transition metal | Transition metal |
| Group / period | 8 / 4 | 11 / 4 |
| State at room temperature | Solid | Solid |
| Atomic mass | 55.845 u | 63.546 u |
| Density | 7.874 g/cm³ | 8.96 g/cm³ |
| Melting point | 1538 °C | 1085 °C |
| Boiling point | 2861 °C | 2562 °C |
| Electronegativity | 1.83 | 1.9 |
| First ionisation energy | 762.5 kJ/mol | 745.5 kJ/mol |
| Electron configuration | [Ar] 3d6 4s2 | [Ar] 3d10 4s1 |
| Discovered by | 5000 BC | Middle East |
Iron
Iron makes up most of the Earth's core, gives the planet its magnetic field, colours the surface of Mars and carries oxygen around your body. It is the metal humans have used most for three thousand years, and each year well over a billion tonnes of steel are made, almost all of it iron. It is cheap, strong, magnetic, and it rusts.
- 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.
Copper
Copper was the first metal people learned to hammer, shape and eventually melt, many thousands of years ago. It gave its name to the Copper Age and, mixed with tin, to the Bronze Age. Today it matters more than ever, because copper carries electricity better than any metal except silver, and the modern world runs on wires.
- 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.
Colour the bubbles by density or melting point and the difference jumps out.
More comparisons
Data from Periodic-Table-JSON (CC BY-SA); temperatures rounded to the nearest degree. Written by Anthony.