Chemistry Class 12

Why does the 4s orbital fill before 3d?

Isn't 3d supposed to come first?

uniboardhub
Asked on 01/11/2025 215 views
1 answers 50 votes

1 Answers

uniboardhub
4 months ago

It's because the energy of 4s is slightly lower than 3d due to shielding and penetration effects. Hence, electrons prefer 4s before 3d when filling.

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