Question

multiple choice question
the sum of the number of protons and the number of neutrons in the nucleus of an atom is the
o mass number
o average atomic mass
o atomic number

Explanation:

The mass number of an atom is defined as the sum of the number of protons and neutrons in the nucleus. The average atomic mass takes into account the relative abundances of different isotopes. The atomic number is just the number of protons.

Answer:

O mass number