Question

The mass number and atomic number of an element are not changed when it emits _______

• A. $\alpha$
• B. $\beta +$
• C. $\gamma$
• D. $\beta -$

Answer 1

The correct option is C $\gamma$

A gamma ray has no mass and no charge.

Emitting a gamma ray makes no difference to the mass number or the atomic number but will make the nucleus more stable.

Emission of alpha particle reduced the mass number by $4$ and atomic number by $2$.

Emission of beta positive decreases the atomic number by $1$ but mass number remains same.

Emission of beta negative increases the atomic number by $1$ but mass number remains same.