For Calcium and Potassium, as 4s is then lower energy than 3d,(and lower means or normally means nearer), would 4s thus be nearer the nucleus than 3d? [closed]








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For Calcium and Potassium, as 4s is then lower energy than 3d, (and lower normally means nearer), would 4s thus be nearer the nucleus than 3d?


For example.


I read in the accepted answer to [Why does the 3rd electron shell start filling up with scandium?](https://chemistry.stackexchange.com/questions/8357/why-does-the-3rd-electron-shell-start-filling-up-with-scandium)


That for Calcium and Potassium, the subshells in order of energy goes 4s then 3d i.e.
1s, 2s, 2p, 3s, 3p, 4s, 3d,..


4s is lower energy than 3d there.


I'm not talking about elements between Scandium and Zinc, where that link explains that for those 10 elements from Scandium to Zinc, 4s is higher energy than 3d but one or two electrons get repelled from 3d to 4s before 3d gets fully filled. Let's put aside the elements from Scandium to Zinc.


No question that for Calcium and Potassium, 4s gets filled before 3d, and 3d doesn't get any electrons there at all.


So for those two elements, Calcium and Potassium, is 4s nearer to the nucleus than 3d?


