Question

How is the mass of the atom calculated?

Answer 1

Answer: By adding the number of protons and neutrons

Explanation:

Protons and neutrons have very similar masses and are used in calculating the mass of an atom. One would calculate the mass of an atom by doing the (mass of a proton) x (# of protons) + (mass of a neutron) x (# of neutrons). Electrons have such a small mass that their mass is considered negligible  and therefore is not included in mass calculations for atoms.

mass of a proton: 1.67262 × 10−27 kg

mass of a neutron: 1.67493×10−27 kg

mass of an electron: 9.10938 × 10-31 kg