Question

An element 'X' has $18$ electrons in 'M' shell and $1$ electron in 'N' shell which is the valence shell. Identify the group and period to which 'x' belongs. Also predict the other elements of the same group.

Answer 1

Element $X$ : $M$ shell$=$ 18 electrons

$M$ shell means $n=$ principal quantum number $=4$ and $N$ shell $=$ $1$ electron.

$N$ shell means $n$ $=$ principal quantum number $=4$

Therefore, element $X=Cu$ with electronic configuration as :-

$Cu$ : ${1s}^2{2s}^2{2p}^6{3s}^2{3p}^6{3d}^{10}{4s}^1$

Other elements of group $11$ are $Cu$ (Copper), SIlver $\left(Ag\right)$ and Gold $\left(Au\right)$.