Question

$^{290}_{82}X\stackrel{\alpha}{\rightarrow}Y\stackrel{e^+}{\rightarrow}Z\stackrel{\beta^-}{\rightarrow}P\stackrel{e^-}{\rightarrow}Q$
In the nuclear emission stated above, the mass number and atomic number of the product Q respectively, are :

• A. 280, 81
• B. 286, 80
• C. 288, 82
• D. 286, 81

Answer 1

Answer: (D)

286, 81

Answer 2

- After $\alpha$ decay, mass number reduces by 4, atomic number by 2: 286, 80.

- After $\beta^+$ emission, atomic number reduces by 1: 286, 79.

- After $\beta^-$ emission, atomic number increases by 1: 286, 80.

- After electron capture, atomic number reduces by 1: 286, 81.