Question

Which one of the following has the highest neutrons ratio?

• A. ${}_{92}{U}^{235}$
• B. ${}_8{O}^{16}$
• C. ${}_{2}H{e}^4$
• D. ${}_{26}F{e}^{56}$

Answer 1

The correct option is A ${}_{92}{U}^{235}$

${}_{92}{U}^{235}$ has the highest neutrons ratio.
Neutrons ratio that is $\frac{n}{p}$ determines the stability of nucleus. (Here, n is number of neutrons and p is number of protons).
For ${}_{92}{U}^{235}$, ,
$n=235-92=143$
$p=92$
Neutrons ratio $=\frac{143}{92}=1.55$
Which is the highest no. So, ${}_{92}{U}^{235}$ is most unstable.