Question

what is the reason for different atomic masses of the isotopes of an element?

Answer 1

The atoms of a chemical element can exist in different types. These are called isotopes. They have the same number of protons (and electrons), but different numbers of neutrons. Different isotopes of the same element have different masses. Mass is the word for how much substance (or matter) something has. Things with different masses have different weights. Because different isotopes have different numbers of neutrons, they do not all weigh the same or have the same mass.

Different isotopes of the same element have the same atomic number. They have the same number of protons. The atomic number is decided by the number of protons. Isotopes have different mass numbers, though, because they have different numbers of neutrons.

The word isotope, meaning at the same place, comes from the fact that isotopes are at the same place on the periodic table.

In a neutral atom, the number of electronsequals the number of protons. Isotopes of the same element also have the same number of electrons and the electronic structure. Because how an atom acts is decided by its electronic structure, isotopes are almost the same chemically, but different physically to their original atoms.

Answer 2

reason for difference in isotopes is due to the difference in the no. of neutones present in nucleus of an atom


example 1H1. protium
1H2. deuterium