Question

Hydrogen exists in three isotopic forms, ${{}^{}}_1{H}^1$, ${}_1{H^2}^{}$ , ${}_1{H}^3$ known as protium, deuterium, and tritium. Why are all the isotopes neutral in nature?

Answer 1

Isotopes are atoms of the same element having same atomic number but different mass numbers. For example, protium $\left(1H1\right)$, deuterium $\left(1H2\right)$, and tritium $\left(1H3\right)$are the three isotopes of hydrogen having atomic number 1 and mass numbers 1, 2, and 3, respectively.

In protium:
$\mathrm{Number}\mathrm{of}\mathrm{protons}=\mathrm{Atomic}\mathrm{number}=1\mathrm{Number}\mathrm{of}\mathrm{electrons}=\mathrm{Number}\mathrm{of}\mathrm{protons}=1\mathrm{Mass}\mathrm{number}=1\mathrm{Number}\mathrm{of}\mathrm{neutrons}=\mathrm{Mass}\mathrm{number}-\mathrm{Atomic}\mathrm{number}=1-1=0$
In deuterium:
$\mathrm{Number}\mathrm{of}\mathrm{protons}=\mathrm{Atomic}\mathrm{number}=1\mathrm{Number}\mathrm{of}\mathrm{electrons}=\mathrm{Number}\mathrm{of}\mathrm{protons}=1\mathrm{Mass}\mathrm{number}=2\mathrm{Number}\mathrm{of}\mathrm{neutrons}=\mathrm{Mass}\mathrm{number}-\mathrm{Atomic}\mathrm{number}=2-1=1$
In tritium:
$\mathrm{Number}\mathrm{of}\mathrm{protons}=\mathrm{Atomic}\mathrm{number}=1\mathrm{Number}\mathrm{of}\mathrm{electrons}=\mathrm{Number}\mathrm{of}\mathrm{protons}=1\mathrm{Mass}\mathrm{number}=3\mathrm{Number}\mathrm{of}\mathrm{neutrons}=\mathrm{Mass}\mathrm{number}-\mathrm{Atomic}\mathrm{number}=3-1=2$

So, in the three isotopes of hydrogen, the number of electrons and protons are the same, which is 1. The difference in the structure of the three atoms is the number of neutrons in them. This leads to the difference in their mass numbers.

Since all the three isotopes of hydrogen have one electron and one proton, hence they are neutral.