Question

Determine the number of neutrons in an isotope of 'H' (mass no. 3).

• A. 1
• B. 2
• C. 0
• D. 3

Answer 1

Answer: (B)

2

Isotopes are atoms of same element with different no of neutrons.
As H,D and T are three different isotopes of H with same no of proton but different no of neutrons.
And mass number is the total number of proton and neutron in an atom.
So mass no. 3 will have $3-1=2$ neutrons.