In an atom, the atomic mass is the sum of the number of
nucleus & neutrons
electrons & protons
protons & neutrons
electrons & neutron
The correct option is C protons & neutrons Neutrons and protons situated in the nucleus of an atom are called nucleons. Atomic mass is the sum of total number of neutrons and protons in the nucleus of an atom. Electrons have a negligible mass compare to protons and neutrons and are hence not considered.