When to move electrons from the s orbital to d orbital

[Jonathan Zuo 2J]

I remember learning that a half filled or completely filled d orbital is more stable and preferred than a d orbital that is not. For example the electron configuration of Nickel would be [Ar]:3d10 instead of [Ar]3d84s2 because the two electrons in the 4s orbital would go to fill the d orbital. Would we do the same for the electron configuration of V ,[Ar]:3d5, or would it be [Ar]3d34s2? Because on a homework problem the correct answer was [Ar]3d34s2. I guess my question is how do I know when to move electrons from the s orbital to the d orbital.

[Nitin Joseph]

The electron config of Nickel would not be
It's
Only one electron can be moved from the s orbital to the d orbital when fulfilling the half-filled subtle rule.
This is why the electron config of Copper is
and not

Similarly, the configuration of Vanadium is as you cannot move two electrons from the s shell into the d shell.
However, the next element in the periodic table, Chromium would have a config of as one electron has been moved to the d subshell.

So basically, when the half-filled d subshell can be achieved by the movement of one electron, an electron should be moved from the s to the d subshell.

Hope this answers your question.