Periodic table
en
fr
ar
es
pt
id
List
Compare
Tables
Quiz
Tools
Printables
Periodic table
›
potassium
›
K-39
Potassium-39 (K-39)
Identity
Protons
19
Neutrons
20
Mass number
39
Mass
38.9637 ± 0.0049 u
Mass excess
-33.807 MeV
Spin
3/2+*
Stability
stable
Natural occurrence
93.26 %
of potassium
Produced by
Ar-39
All isotopes of potassium