Question

State whether the given statement is correct or not.

${}_{92}^{235}\text{U}$ decays to form ${}_{82}^{207}\text{Pb}$ along with emission of $7\alpha$ and $4\beta$-particles.

• A. True
• B. False

Answer 1

The correct option is A True

The given statement is True.
${}_{92}^{235}\text{U}$ decays to form ${}_{82}^{207}\text{Pb}$ along with emission of 7α and 4β-particles.
${}_{92}^{235}\text{U}{\underset{-4\beta }{\overset{-7\alpha }{\to }}}_{82}^{207}\text{Pb}$
It is actinium series (4n+3 series).
The remainder is three when the mass number is divided by four.
When an alpha particle is emitted, the atomic number decreases by 2 and the mass number decreases by 4.
When a beta particle is emitted, the atomic number increases by1 and the mass number remains unchanged.
When 7 alpha particles and 4 beta particles are emitted, the atomic number decreases by $7\left(2\right)-4\left(1\right)=10$ and the mass number decreases by $7\left(4\right)-4\left(0\right)=28$