How can we identify the number of group from electronic configration of any element if it ended in 3d^8 4S^2 I know group no. = total no. of valence but whats the valence here in this situation?

1 Answer

The electron configuration must finish like this: 4s^2 3d^8 .

Explanation:

The element is Nickel ("Ni") with 28 valence eletrons.

The period is identified looking at the level of energy (n) which is the number 4, for the 4s orbital. This means "Ni" is in the fourth period in the periodic table.

The group number is normally related to the valence electrons. However, this relation does not include the transition metals from group "VIIIB" (e.g. "Fe", "Co", "Ni", . . . ).