Question

Match the following:

Column-I	Column-II
$\left(A\right)$ ${}_6^{14}C$	$\left(i\right)$ Unstable and $\beta$-emitter
$\left(B\right)$ ${}_{11}^{24}Na$	$\left(ii\right)$ Stable
$\left(C\right)$ ${}_7^{13}N$	$\left(iii\right)$ Unstable, positron emitter
$\left(D\right)$ ${}_6^{13}C$	$\left(iv\right)$ Unstable, $\alpha$-emitter

Correct matching is/are :

• A. $A$ only
• B. $C$ only
• C. $B$ and $D$
• D. $A$ and $C$

Answer 1

Answer: (D)

$A$ and $C$

Generally for elements with atomic number less than 20, nuclei with a neutron to proton ratio 1:1 are stable.

There are two stable isotopes of carbon, carbon 12 and carbon 13. Carbon 14 is unstable and decays by beta emission into nitrogen 14 which is stable with a neutron to proton ratio of 1:1.

Nitrogen 13 is also unstable with a neutron to proton ratio less than 1 and decays into carbon 13 by positron emission.

Sodium 23 is the only stable isotope of sodium.