Question

Oxygen has three isotopes${\mathrm{O}}^{16},{\mathrm{O}}^{17},{\mathrm{O}}^{18}.$ how do the atoms of these isotopes differ?

Answer 1

• The isotopes of a chemical element are a group of atoms that have the same atomic numbers but different mass numbers.
• This implies that all isotopes of an element have the same number of protons in their atomic nuclei and the same number of electrons in the electron cloud surrounding the nucleus.
• However, they differ in the total number of neutrons present in their respective atomic nuclei.

Isotope of oxygen	Number of electrons	Number of proton	Number of neutrons
${\mathrm{O}}^{16}$	8	8	8
${\mathrm{O}}^{17}$	8	8	9
${\mathrm{O}}^{18}$	8	8	10

Hence, three isotopes${\mathrm{O}}^{16},{\mathrm{O}}^{17},{\mathrm{O}}^{18}.$ contain the same number of electrons and protons but a different number of neutrons in their nucleus.