GENERAL KNOWLEDGE

Detailed explanation-1: -The number of protons in a nucleus is called the atomic number and always equals the number of electrons in orbit about that nucleus (in a nonionized atom). Thus, all atoms that have the same number of protons–the atomic number–are atoms of the same element.

Detailed explanation-2: -The number of protons in an atom is called the ATOMIC NUMBER of the element. Each element therefore has a unique atomic number.

Detailed explanation-3: -The atomic number is the number of protons in an atom, and isotopes have the same atomic number but differ in the number of neutrons.