Question

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

• A. 6
• B. 5
• C. 4
• D. 3

Answer 1

The correct option is A 6

In tritium nucleus there is one proton and 2 neutrons
$\therefore n+p=3$
In deuterium nucleus there is one proton and one neutron
$\therefore n+p=2$
In protium nucleus there is one proton and no neutron
$\therefore n+p=1$
Total $=3+2+1=6$