Exceptions to Trends

[Samantha Chung 4I]

I remember when writing electronic configuratons, there were two exceptions Chromium and copper, I think professor lavelle mentioned "why" these are exceptions in class. Can someone re-explain this to me?

Thanks!

[Rithana Srikanth 3L]

Half-filled and completely filled d orbitals have lower energy which makes them more stable, hence electrons will tend to rearrange themselves towards this state. In chromium and copper, an electron is excited from the 4s orbital to the 3d orbital in order to make the 3d orbital half filled (in the case of chromium) or completely filled (in the case of copper).

[Haowen_Liang_3E]

The profession also mentions that what he said is a theory of why the phenomenon occurs, so maybe the science world doesn't fully understand it yet.

[Raymond Ko 1H]

The exceptions to the trends of electron configuration arrange in different ways because the goal of atoms is to arrange their electrons in the most stable manner, with the lowest energy. Also remember that when you are turning atoms into anions and removing electrons, always take electrons from the top shell first, the valence shell.