Question

The atomic mass of an element is

Answer 1

Here are the answers to the question. Make sure to give a valid reason, please.

A. the sum of the protons and neutrons in one atom of the element.

B. a ratio based on the mass of a carbon-12 atom.

C. a weighted average of the masses of an element's isotopes.

D. twice the number of protons in one atom of the element.