Cu (Z=29): expected [Ar]3d⁹4s² but actual [Ar]3d¹⁰4s¹ (completely filled d). Cr (Z=24): expected [Ar]3d⁴4s² but actual [Ar]3d⁵4s¹ (half-filled d). Both Cu and Cr deviate from Aufbau.
Take chapter-wise tests, track your progress, and master Atomic Structure.
Start Free Practice →