The atomic number of an atom is equal to the:

Correct option is A

Correct Answer: (A) Total number of protons present in the nucleus of an atom

Explanation:

Atomic Number Definition:

·         The atomic number of an atom is defined as the number of protons in the nucleus of the atom.

·         This number is unique for each element and determines its position in the periodic table.

Why not other options?

·         The atomic number is not the sum of electrons and neutrons. Electrons are equal to protons in a neutral atom, but neutrons are not involved in the atomic number.

·         Electrons do not reside in the nucleus, so this is incorrect. Also, the atomic number is not half the number of electrons.

·         The sum of protons and neutrons represents the mass number, not the atomic number.

Example:

• For hydrogen, the atomic number is 1 because there is 1 proton in its nucleus.
• For carbon, the atomic number is 6 because there are 6 protons in its nucleus.