Question

A plot of the number of neutrons ($N$) against the number of protons ($P$) of stable nuclei exhibits upward deviation from linearity for atomic number, $Z>20$. For an unstable nucleus having $\frac{N}{P}$ ratio less than 1, the possible mode(s) of decay is/are

• A. Orbital or $K$-electron capture
• B. Neutron emission
• C. ${\beta }^{-}$-decay ($\beta$ emission)
• D. ${\beta }^{+}$-decay (positron emission)

Answer 1

Answer: (A), (D)

${\beta }^{+}$-decay (positron emission)

When $\frac{N}{P}$ ratio is less than one, then proton changes into neutron.

Positron emission$:{}_1^{1}H\underset{}{\overset{}{\to }}{}_0^{1}n+{}_{+1}^0\beta$

$K$-electron capture$:{}_1^{1}H+{}_{-1}^{0}e\underset{}{\overset{}{\to }}{}_0^{1}n+X\text{-}rays$