The Mass number of an element is the?

A. number of protons plus electrons

B. number of protons only

C. number of protons plus neutrons

The mass number of an element is the sum of the number of protons plus neutrons.

Answer: Option C

Explanation:

The element's mass number refers to the summative number of neutron and proton in the nucleus. In the nucleus there is the total number of protons and neutron, summed together to form the atomic mass.

Atomic mass is similar as the mass number in representation. Therefore, we have the following formula for the mass number,

Mass number of an element=Number of protons+Number of neutrons

The mass number of an element is the number of protons plus neutrons.

Explanation:

The mass number of an element is the number of protons plus neutrons, so the correct answer is the option C.