Question

${}_{95}A{m}^{241}and{}_{90}T{h}^{234}$ belong respectively to:

• A. 4n and (4n +1) radioactive disintegration series
• B. (4n + 1) and (4n + 2) radioactive disintegration series
• C. (4n + 1) and (4n + 3) radioactive disintegration series
• D. (4n +1) and 4n radioactive disintegration series

Answer 1

The correct option is D (4n +1) and 4n radioactive disintegration series

For ${}_{95}A{m}^{241}$ ,mass number is 241.
Let’s divide 241 with four, reminder is 1, so it belongs to 4n+1 series.
For Thorium, mass number is 234.
Let’s divide 234 with four, reminder is 0, so it belongs to 4n series.