Question

All isotopes of a particular element have the same atomic number. How then do the isotopes of a particular element differ?

Answer 1

The number of neutrons vary.

Explanation:

Atomic Number: The number of protons in an atom, NOT the number of neutrons

Isotope: An element with a varying number of neutrons

Remember, we CANNOT change the number of protons without changing the element.

However, by adding or subtracting neutrons, we can change an element's properties.

For an example: https://www.boundless.com/chemistry/textbooks/boundless-chemistry-textbook/nonmetallic-elements-21/hydrogen-148/isotopes-of-hydrogen-573-3644/

This site goes into the different isotopes of H.