Question

Isotopes have same number of ________________but different number of neutrons.

Answer 1

Isotopes have the same number of protons but a different number of neutrons.

Example

• ${\mathrm{Cl}}_{17}^{35},{\mathrm{Cl}}_{17}^{37}$ are two isotopes of element Chlorine with mass number $35$ and $37$respectively.
• The atomic number of Chlorine is$17$, which means that every chlorine atom has $17$ protons but the number of neutrons (mass number- atomic number) of these isotopes are $18\mathrm{and}20$ respectively.