Question

Question 07

Two atoms are said to be isobars if ?

(a) They have same atomic number but different mass number

(b) They have same number of electrons but different number of neutrons

(c) They have same number of neutrons but different number of electrons

(d) Sum of the number of protons and neutrons is same but the number of protons is different

Answer 1

Isobars have the same mass number (i.e., sum of protons and neutrons) but different atomic number (i.e., number of protons). e.g., ${}_{16}A{r}^{40}$ and ${}_{19}{K}^{40}$ are isobars.

$\begin{array}{cc}{}_{18}{A}^{40}& {}_{19}{K}^{40}\\ Atomicnumber=18& Atomicnumber=19\\ Massnumber=40& Massnumber=40\end{array}$