When ${^{232}_{92}Th}$ changes into ${^{208}_{82}Pb}$, the number of $α$ and $β^-$ particles emitted are
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $α = 6;β=2$
$^{232}_{92}\text{Th} \rightarrow \, ^{208}_{82}\text{Pb}$
$\text{Let number of } \alpha = a,\quad \beta^- = b$
$\text{Mass number: } 232 - 4a = 208$
$4a = 24 \Rightarrow a = 6$
$\text{Atomic number: } 92 - 2a + b = 82$
$92 - 12 + b = 82$
$80 + b = 82 \Rightarrow b = 2$