Question

Which of the following is not related as isotones with others?

• A. ${}_{14}^{30}Si$
• B. ${}_{15}^{31}P$
• C. ${}_{16}^{32}S$
• D. ${}_{17}^{35}Cl$

Answer 1

The correct option is D ${}_{17}^{35}Cl$

Isotones are atoms of different elements containing the same number of neutrons.

Now, Let's calculate the number of neutrons.

Number of neutrons = Mass number - Number of protons

${}_{15}^{30}Si\to 30-14=16$

${}_{15}^{31}P\to 31-15=16$

${}_{16}^{32}Si\to 32-16=16$

${}_{17}^{35}Si\to 35-17=18$

Here ${}_{15}^{30}Si$ , ${}_{15}^{31}P$ and ${}_{16}^{32}S$ are isotones. ${}_{17}^{35}Cl$ is the odd one as per the relation asked.