Which of the following are isotopes and which are isobars?

Argon, Deuterium, Calcium, Tritium, Protium

What is the reason for the slightly different physical properties of all the isotopes of an element?

Explain why, the atomic masses of many elements are in fractions and not whole numbers.

Hydrogen has three isotopes written as:

Explain why:

(i) these isotopes have almost identical chemical properties.

(ii) they are electrically neutral.

Given that the percentage abundance of the isotope is 90% and that of the isotope is 10%, calculate the average atomic mass of neon.