Question

A radioactive nucleus with Z protons and N neutrons emits ana-particle, 2 b-particles and2 gamma rays. The number of protons and neutrons in the nucleus left after the decay respectively, are –

• A. Z – 3, N – 1
• B. Z – 2, N – 2
• C. Z – 1, N – 3
• D. Z, N – 4

Answer 1

Answer: (D)

Z, N – 4

Answer 2

_zX^Z+N$\xrightarrow { 1 \alpha }$_Z–2P^Z+N–4$\xrightarrow { 2 \beta ^ { - } }$_ZQ^Z+N–4$\xrightarrow { 2 \gamma }$
_ZQ^Z+N–4, N_P = Z, N_n = N – 4