Question

${}_{20}{}^{40}\mathrm{Ca}$ and ${}_{18}{}^{40}\mathrm{Ar}$ are called isotopes.

• A. True
• B. False

Answer 1

The correct option is B False

1. Elements with same atomic number but different mass number are called as isotopes.
2. $\mathrm{Ca}$ has atomic number $20$ and $\mathrm{Ar}$ has atomic number $18$, which are different.
3. Since, the given elements does not has same atomic number, they are not isotopes.

Hence, the given statement is False.