Question

How many neutrons does potassium have? 2 19 20 39

Answer 1

Answer: The number of neutrons in potassium atom are 20.

Explanation:

Atomic number is defined as the number of protons that are present in an atom. It is represented as 'Z'.

Z = Number of protons

Mass number of an atom is defined as the sum of number of protons and number of neutrons present in an atom. It is represented as 'A'.

A = Number of neutrons + Number of protons

For Potassium atom, the value of A is 39 and its atomic number is 19.

39 = Number of neutrons + 19

Number of neutrons = 39 - 19 = 20

Hence, the number of neutrons in potassium atom are 20.

Answer 2

The number of neutrons is determined from the difference of the atomic weight and atomic number. The atomic weight is 39 while the atomic number is 19. Thus, the number of neutrons is 20.