Orbital Filling Sequence And Energy Levels
=3) Orbitals with the lowest sum of n + l are filled first. If two orbitals have the same n + l value, the one with the lower n fills first. For example: 1s: n=1, l=0 → n+l=1 2s: n=2, l=0 → n+l=2 2p: n=2, l=1 → n+l=3 3s: n=3, l=0 → n+l=3 Hence, 2