Question

Atomic number of an element represents ______.
A) Number of neutrons in the nucleus
B) Atomic mass of an element
C) Valency of an element
D) Number of protons in the nucleus

Answer 1

Hint: An element possesses the number of protons, electrons, and neutrons present in it. The values such as molecular weight and atomic weight are very much dependent on the presence of the number of protons, electrons, and neutrons.

Complete step by step answer:
1) First of all let's understand the structure of the element and the factors present in it which can determine the atomic values of that element.
2) Each atom possesses a nucleus at the center and orbitals which are present around it.
3) The nucleus of an element possesses the protons and neutrons and the orbitals which are present around it possess the electrons revolving in that orbital.
4) The number of protons that are present in an atom is always equal to the number of electrons that are revolving in an orbital around the nucleus. The number of neutrons may vary according to the element.
5) The protons have a positive charge on it, the neutrons don’t have any charge on it, and the electrons are negatively charged species.
6) As the neutrons have no charge on it and the protons are positively charged which are present on the nucleus of that element on which the atomic number of that element depends.
7) Therefore, we can say that the atomic number of elements represents the number of protons in the nucleus which shows the option D as a correct choice.
Thus option D is the correct answer.


Note:
The elements are placed in the periodic table according to their atomic number sequentially. The number of electrons is always equal to the number of protons present in that element but the number of neutrons may be different and this leads to the isotopes of that element.