Question

which determines the identity of an element?
a. number of energy levels
b. number of neutrons in the nucleus
c. number of protons inside the nucleus
d. number of electrons surrounding the atom

Explanation:

The identity of an element is determined by the number of protons in the nucleus. This is because each element has a unique atomic number which is equal to the number of protons. Changing the number of protons changes the element. Neutrons affect isotopes, electrons affect ions and energy levels are related to electron - shell configuration but not the elemental identity.

Answer:

C. number of protons inside the nucleus