Question

The sum of the number of neutrons and protons in an isotopes of hydrogen is:

• A. 4
• B. 5
• C. 6
• D. 3

Answer 1

Answer: (D)

6

In ${}_1^{3}H$, there are 1 proton and 2 neutrons.

In the tritium nucleus, there is one proton and 2 neutrons

∴ n + p = 3

In the deuterium nucleus, there is one proton and one neutron

∴ n +p = 2

In protium nucleus there is one proton and no neutron

∴ n + p = 1

Total = 3 + 2 +1 = 6