Question

Thorium radioactive series is also called as 4n series.

• A. True
• B. False

Answer 1

The correct option is A True

True. Because the two pertinent decay processes result either in no change or in a change of four units in the mass number, the mass numbers of all the members of each series are divisible by four with a constant remainder. Within each series, therefore the mass number of the members may be expressed as four times an appropriate integer (n) plus the constant for that series; thus the thorium series is sometimes called $4n$ series.