Question

___ are atoms of the same element, which have the same number of protons but different mass numbers.

Answer 1

Isotopes:

1. Isotopes are species that have the same number of protons but a different number of neutrons.
2. Hence, they have the same atomic number but a different mass number.

Example:

1. Hydrogen has three isotopes, namely: protium, deuterium, and tritium.
2. All the three isotopes have one proton but have different neutrons, i.e., one, two, and three, respectively.

Hence, isotopes are atoms of the same element, which have the same number of protons but different mass numbers.