GENERAL KNOWLEDGE

Detailed explanation-1: -The mass number of an atom is its total number of protons and neutrons. Atoms of different elements usually have different mass numbers, but they can be the same. For example, the mass number of argon atoms and calcium atoms can both be 40.

Detailed explanation-2: -The mass number is defined as the total number of protons and neutrons in an atom. It can be calculated by adding the number of neutrons and the number of protons (atomic number) together. Consider Table 4.17.

Detailed explanation-3: -The atomic number is the number of protons in an element, while the mass number is the number of protons plus the number of neutrons.

Detailed explanation-4: -The positively charged protons tend to repel each other, and the neutrons help to hold the nucleus together. The number of protons is the atomic number, and the number of protons plus neutrons is the atomic mass. For hydrogen, the atomic mass is 1 because there is one proton and no neutrons.

Detailed explanation-5: -mass number, in nuclear physics, the sum of the numbers of protons and neutrons present in the nucleus of an atom.