Figure 1. Variation of (n+ℓ) and (n+0.75ℓ) versus the atomic number Z

From

Beyond the Madelung-Klechkowski Rule of aufbau Orbital Filling Principle

Tangour Bahoueddine

World Journal of Chemical Education. 2015, 3(6), 160-167 doi:10.12691/wjce-3-6-5