Question

what does an atomic number represent in an atom?
number of protons
number of protons and neutrons
number of electrons
number of neutrons

Explanation:

The atomic number of an atom is defined as the number of protons in its nucleus. This number determines the element's identity. 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 is the mass - number.

Answer:

number of protons