Question

multiple - choice question
what is atomic mass?
the mass of the total number of protons plus the total number of electrons averaged across all the isotopes that exist.
the mass of the total number of protons plus the total number of neutrons averaged across all the isotopes that exist.
rewatch

Explanation:

Atomic mass is calculated as the weighted - average mass of all naturally occurring isotopes of an element, taking into account the number of protons and neutrons. Electrons have negligible mass compared to protons and neutrons and are not included in the calculation of atomic mass.

Answer:

The mass of the total number of protons plus the total number of neutrons averaged across all the isotopes that exist.