Question

An element x has 2 electrons in k-shell
8 elections in L. shell and 5 electrons in
M shell
(a)Size of x-ion is
X-ion is greater than that of
X-atom though
both contain the same
number of
Protons.why?​

Answer 1

So, in K shell, 2 electrons 1s 2 are presentIn L shell, 8 electrons 2s 22p 6 are presentIn M shell, 13 electrons 3s 2 3p 6 3d 5 are presentIn N shell, 1 electron 4s 1 is present.

Answer 2

Question : An element x has 2 electrons in K-shell, 8 elections in L-shell and 5 electrons in M-shell. Size of X-ion is greater than that of X-atom though both contain the same number of protons. Why?

Answer : An element X has 2 electrons in K-shell, 8 electrons in L-shell and 5 electrons in M-shell. So, according to the electronic configuration, $\sf 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{3}$, the element is phosphorus. Let's assume, the X-ion is phosphide ion, so the electronic configuration of $\sf P^{3-}$ is $\sf 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6}$. Now, the size of X-ion, which is an anion is greater than that of X-atom because it gained 3 electrons to become stable and thus, it's size increased.