Question

A certain nucleus X has a mass number of 16 and an atomic number of 7. Find the number of neutrons. The nucleus X emits one β-particle. Write the symbol of the new nucleus and express the change using a reaction.

Answer 1

Mass number = No. of protons + No. of neutrons

Atomic number = No. of protons

∴ No. of neutrons = Mass number − Atomic number 

= 16 − 7

= 9

Element X can be written as \[\ce{_7^16X}\].

After the loss of one β-particle, the mass number will remain the same, and the atomic number will increase by 1. The element X changes to Z.

\[\ce{_7^16X -> _8^16Z + _-1^0e + γ - ray}\]