Question

Ll atoms of the element potassium have 19 protons. One of the most stable types of potassium atoms has the mass number 39.

How many neutrons make up one of these potassium atoms?

Answer 1

The most stable type of potassium atom with a mass number of 39 contains 20 neutrons.

Step-by-step explanation:

This is because the mass number of an atom is the sum of the number of protons and neutrons in the nucleus. In this case, the atom has 19 protons, and its mass number is 39, so it must have 20 neutrons to satisfy this relationship.