Question

atomic composition quick check
how is the mass number of an atom calculated? (1 point)
○ electrons plus neutrons
○ protons plus neutrons
○ total number of electrons
○ total number of protons

Explanation:

The mass number of an atom is calculated by adding the number of protons and neutrons. Electrons have negligible mass compared to protons and neutrons and do not contribute significantly to the mass number calculation.

Answer:

protons plus neutrons