K
Potassium · element 19
Alkali Metal · Solid at room temperature
Potassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name is derived. In the Periodic table, potassium is one of seven elements in column (group) 1 (alkali metals):they all have a single valence electron in their outer electron shell, which they readily give up to create an atom with a positive charge - a cation, and combine with anions to form salts.
Key facts
Atomic mass
39.09831 u
how heavy one atom is
Phase (room temp.)
Solid
Density
0.862 g/cm³
how tightly packed it is
Melting point
336.7 K (64 °C)
when solid turns to liquid
Boiling point
1032 K (759 °C)
when liquid turns to gas
Period
4
its row in the periodic table
Group
1
its column in the periodic table
Block
S-block
the neighbourhood it lives in
Electronegativity
0.82
how strongly it pulls electrons
Electron configuration
[Ar] 4s1
where its electrons live
Shells
2 · 8 · 8 · 1
electrons in each layer, inside to out
Discovered by
Humphry Davy
who found it
Appearance
silvery gray
what it looks like
Source: Wikipedia