Ncert Exercises & Solutions

When a nucleus in an atom undergoes a radioactive decay, the electronic energy levels of the atom:

1.	do not change for any type of radioactivity
2.	change for α and β -radioactivity but not for γ -radioactivity
3.	change for α -radioactivity but not for others
4.	change for β -radioactivity but not for others

(2) Hint: The atomic mass and atomic number changes for

α

and

β

-particle decay.

Step 1: Find the change in energy levels for different types of decay.

α

β

particle carries one unit of a negative charge, an

α

-particle carries 2 units of positive charge and

γ

(particle) carries no charge, therefore electronic energy levels of the atom changes for

α

and

β

decay, but not for

γ

-decay.