Atomic No. Order:

Alphabetic Order:

Periodic Table

2, 8,

8, 1

H
1

Li
3

Na
11

K
19

Rb
37

Cs
55

Fr
87

Uue
119

Uhe
169

Bue
219

Potassium

Symbol

Atomic Number

Relative Atomic Mass
¹²C = 12.0000

39.0983 (1) [Since 1979]

Atomic Radius pm

227

First Ionisation Energy
kJ mol ^-1

418.8

Ionisation Energy (eV)

4.3407

Electronegativity

0.82

Density
kg m ^-3

862 [293 K]
828 [l., m.p.]

Molar Volume cm ³

45.36

Thermal Conductivity
W m ^-1 K ^-1

102.4 [300 K]

Melting Point K

336.80

Boiling Point K

1047

Number of Isotopes

Isotope Atomic mass/u Mole fraction

39K 38.963 7069(3) 0.932 581(44)
40K 39.963 998 67(29) 0.000 117(1)
41K 40.961 825 97(28) 0.067 302(44)

Inner + outer Shells

Inner + outer Orbitals

Filling Orbital

4s ¹

Ground State Electron
Configuration

[Ar]

4s ¹

Ground State Electron
Configuration with
free Orbitals (n= 17)

0, 0, 10, 7

Ground State Electron
Configuration with
compressed Orbitals (n= 24)

0, 0, 0, 24

Singularity

	s		p	d	f	g	h	i	j
1	2
2	2		6
3	2		6	10
4	1	1	6	10	14
5
6
7

Term Symbol

²S _1/2

Discovery

It was first isolated
by the British chemist Humphry Davy (London, England) in 1807 from electrolysis of potash (KOH).

Name Derived From

The name derives from the English "potash" or "pot ashes" because it is found in caustic potash (KOH).

The chemical symbol [K] derives from the Latin kalium via the Arabic qali for alkali.

APSIDIUM ©	Created:	2002-06-04	019.pdf
	Page update:	2004-06-20	019.pdf