Question

the atomic number indicates the number of ______ in an atom.

a. protons
b. protons and neutrons
c. electrons
d. neutrons

Explanation:

The atomic number of an element is defined as the number of protons in the nucleus of an atom of that element. In a neutral atom, the number of electrons equals the number of protons, but the atomic number specifically refers to protons. The sum of protons and neutrons gives the mass - number. Neutrons alone do not define the atomic number.

Answer:

A. protons