Question

Give the number of the group and the period of the element having three shells with three electrons in the valence shell.

Answer 1

Answer=13th group and 3rd period

First, we write the electronic configuration of the given element having three shells with three electrons in the valence shell.

electronic configuration= ${\text{1s}}^2{\text{2s}}^2{\text{2p}}^{6}3s^2{\text{3p}}^1$

Concept= Group of the element is predicted from the electrons present in the outermost (n) or penultimate (n-1) shell.

The principal quantum number of the valence shell represents the period of the element.

Here, the given element belongs to the p block.

For p-block elements;

group number = 10 + number of ns and np electrons

therefore; group number = 10 + number of ns and np electrons=13.

Also the principal quantum number is 3,

Therefore, period= 3