The atomic number of Potassium is 19 and its mass number is 39. The number of neutrons its atom isÂ ............_x005F_x000D_

The atomic number of Potassium is 19 and its mass number is 39. The nu

1.	The atomic number of Potassium is 19 and its mass number is 39. The number of neutrons its atom isÂ ............_x005F_x000D_
A.	19
B.	39
C.	20
D.	58
Answer» D. 58