Chromium Question

[D.D.S.]

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Hi guys, why is there only 1 electron in the 4s subshell and not 2??

electron config of chromium: Cr 1s2 2s2 2p6 3s2 3p6 4s1 3d5


Thanks

 

[TimeforDAT]

Chromium and Copper are exceptions to the electron configuration rules. Based on what you know about electron configuration, yes it should be 4s2 3d4...however it is more stable for chromium to have all five of the d orbitals filled with half spins rather than having only four d orbitals filled with half spins, so one of the s orbital electrons gets filled to the d orbital. Same reasonining will apply to copper as well

 

[D.D.S.]

Thank you!