There are three types of electrons:-
1) S-electrons (these go round in a spherical shape).
2) P-electrons (these go round in a dumbell-like shape).
3) D-electrons. (treble clef shape).
At A-level, subshell notation is used in electron configuration.
Group 1 and 2 are known as the S-block. They have S-electrons as their outer most shell.
Transitional elements are the D-block. They have D-electrons as their outer shell.
Groups 3-8 are the P-block. They have…