Question

The polonium isotope ${}_{84}^{210}Po$ is unstable and emits a 10 MeV alpha particle. The atomic mass of ${}_{84}^{210}Po$ is 209 .983 U and that of ${}_2^{4}He$ is 4.003U. the atomic mass of the daughter nucleus is

• A. 210 U
• B. 208 U
• C. 82 U
• D. 206 U

Answer 1

The correct option is D 206 U

Let the atomic nuclei be ${}_X^Y\text{A}$

${}_{210}^{84}\text{Po}{\to }_X^Y\text{A}{+}_4^2\text{He}+10Mev$

So, $X=209.983-4.003=205.98$

$\approx 206u$

So, the correct option will be $\left(D\right)$