Argon Calcium

Potassium (K)

From Wikipedia, the free encyclopediaPotassium 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.

Potassium in the periodic table

Symbol

Atomic number

Group

Period

Block

Element category

Alkali Metal

Physical properties

Phase at STP

Solid

Density

0.862 g/cm³

Atomic weight

39.0983 u

Melting point

336.7 K
63.55 °C
146.39 °F

Boiling point

1032 K
758.85 °C
1397.93 °F

Atomic properties

Electronegativity (Pauling Scale)

0.82

Electron affinity

48.383 kJ/mol

Oxidation states

−1, +1
(a strongly basic oxide)

Ionization energies

1	418.8 kJ/mol
2	3052 kJ/mol
3	4420 kJ/mol
4	5877 kJ/mol
5	7975 kJ/mol
6	9590 kJ/mol
7	11343 kJ/mol
8	14944 kJ/mol
9	16963.7 kJ/mol
10	48610 kJ/mol
11	54490 kJ/mol
12	60730 kJ/mol
13	68950 kJ/mol
14	75900 kJ/mol
15	83080 kJ/mol
16	93400 kJ/mol
17	99710 kJ/mol
18	444880 kJ/mol
19	476063 kJ/mol

Electron configuration

Elektronkonfiguration (shorthand)

[Ar] 4s¹

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

Electrons per shell

2, 8, 8, 1

History

Discovered

1807

Discovered by

Humphry Davy