For emission of $\alpha$-particle from uranium nucleus, shortage of two electrons in thorium is due to :
${}_{92}{U}^{235}{-}_{2}H{e}^4{\to }_{90}T{h}^{231}$

Q. Let us consider emission of $\alpha$-particle from uranium nucleus:
${}_{92}{U}^{235}{\to }_2{He}^4\to$ ${}_{90}{Th}^{231}$
$e=92$ $e=0$ $e=90$
$p=92$ $p=2$ $p=90$
$n=143$ $n=2$ $n=141$
Shortage of two electrons in thorium is due to:

Q. For the β+(positron) emission from a nucleus, there is anothercompeting process known as electron capture (electron from an innerorbit, say, the K–shell, is captured by the nucleus and a neutrino isemitted).1A A e X Y Z Z ν++ → + −Show that if β+emission is energetically allowed, electron captureis necessarily allowed but not vice–versa.

Q.

For the (positron) emission from a nucleus, there is another competing process known as electron capture (electron from an inner orbit, say, the K−shell, is captured by the nucleus and a neutrino is emitted).

Show that if emission is energetically allowed, electron capture is necessarily allowed but not vice−versa.