Potassium

Chaitra 26/06/2026 19:58:08 Updated 26/06/2026 19:58:08

Property	Value
Atomic Number	19
Element	Potassium
Symbol	K
Atomic Mass	39.098 u
Number of Neutrons	20 (most common isotope, Potassium-39)
Number of Protons	19
Number of Electrons	19
Period	4
Group	1
Phase	Solid
Radioactive	No (Note: contains naturally occurring radioactive isotope K-40 in trace amounts)
Natural	Yes
Metal	Yes
Nonmetal	No
Metalloid	No
Type	Alkali Metal
Atomic Radius	243 pm
Electronegativity	0.82 (Pauling scale)
First Ionization Energy	4.341 eV
Density	0.862 g/cm³
Melting Point	63.5 °C
Boiling Point	759 °C
Number of Isotopes	3 naturally occurring (K-39, K-40, K-41)
Discoverer	Humphry Davy
Year	1807
Specific Heat	0.757 J/g·K
Number of Shells	4
Number of Valence Electrons	1