Question

Decrease in atomic number is observed during which of the following?

• A. alpha emission
• B. beta minus emission
• C. positron emission
• D. electron capture

Answer 1

Answer: (A), (C), (D)

The correct options are
A alpha emission
C positron emission
D electron capture

Alpha emission : ${}_Z^{A}X\to$ ${}_{Z-2}^{A-4}Y+\alpha$

Positron emission : ${}_Z^{A}X\to$ ${}_{Z-1}^{A}Y$ $+$ ${}_1^{0}e$

Electron capture : ${}_Z^{A}X$ ${+}_{-1}^{0}e\to$ ${}_{Z-1}^{A}Y$

Hence decrease in atomic number is observed in alpha emission, positron emission and electron capture whereas increase in atomic number is seen during $\beta$ emission.