In simple terms, how do you write complete orbital configuration? What exactly does that mean?
Orbital configuration is just how many electrons are in each orbit of the atom. The electons fill in a specific order which is by spfd and period on the periodic table. Two electron go in the s orbital, 6 in the p, 10 in the d and 14 in the f. This website shows the filling order, each box on the periodic table represent a spot filled by an electron. So for example if you had to write the electron configuration for Boron it would be 1s2, 2s2, 2p1. The 1s2 corresponds to the H and He box in the 1st period. The 2s2 corresponds to the Li and Be box in the 2nd period and the 2p1 corresponds to the B box in the 2nd period.