Question

What happens to the atomic number of an element when it emits an $\alpha$-particle ?

• A. Increase by $2$
• B. Decrease by $2$
• C. Increase by $4$
• D. Decrease by $4$

Answer 1

The correct option is B Decrease by $2$

The emission of an alpha particle from a nucleus reduces the mass number of the nucleus by $4$ and the atomic number by $2$.