Question

What are 3 things isotopes of an element have in common?

Answer 1

Hint: Isotopes of any element are the property of that same element to possess different atomic masses. Isotopes are the same elements having a difference of one, two, or three units in their relative atomic masses. Atomic mass is the sum of the number of protons and neutrons.

Complete answer:
Isotopes are the atoms of the same element having variable atomic masses. There are three characteristic features that are common in the isotopes of any element.
1. Isotope of every element contains the same number of protons. Proton is a positive sub – atomic particle, present in the nucleus and hence called nuclear proton. Through protons the atomic number to various elements are given, as atomic number = number of protons in an element. For example, hydrogen has Z = 1, helium has Z = 2.
2. As the number of electrons in any element is equal to the number of protons, hence, the number of electrons in the isotopes of any element is also the same.
3. Same isotopes contain the same number of neutrons in their nuclei. Therefore, the numbers of protons added to the number of neutrons give the atomic mass of the elements and thus their isotopes.
For example, isotopes of hydrogen, protium (${}_{1}^{1}H$), deuterium (${}_{1}^{2}H$), and tritium (${}_{1}^{3}H$), protium contains 1 proton and 0 neutrons, so mass 1, deuterium has 1 proton and 1 neutron so its mass is 2, while tritium has 1 proton and 2 neutrons, so its mass is 3.
Hence, the 3 common things in isotopes are explained.

Note:
The representation ${}_{1}^{1}H$ shows, subscript as the atomic number, and the superscript as the atomic mass of any element. In any element the protons and neutrons together are called as nucleons whose sum decides the atomic masses of elements. The property of isotopes is due to the variable neutrons that are present in the nucleus, hence isotopes are used in nuclear reactions.