SSC MTS EXAM

Detailed explanation-1: -The mass of the atom is concentrated in the nucleus (protons and neutrons are about 2000 times as heavy as electrons). 2. The atomic number (the number of protons) determines which element an atom is.

Detailed explanation-2: -Most of the atom’s mass is concentrated in a central nucleus, which contains protons and neutrons. The nucleus is surrounded by much less massive electrons, which account for most of the volume occupied by the atom.

Detailed explanation-3: -The mass of an atom is contributed by proton and neutron. An electron has a negligible mass which does not contribute much to the mass of an atom. As protons and neutrons lie inside the nucleus, so mass of an atom is majorly present in the nucleus.