Electron configurations for ions

[chemgal4L]

I have a really hard tim figuring out the electron configurations for ions. How do you know whether the ion will lose valence electrons from the d orbital first or if it will lose them from the s orbital first. I know there are exceptions to copper and chromium, but how about all of the other d block metals.

[Christina Quigg 4G]

For the d block electrons, with the exception of chromium and copper, the 4s electrons will be lost first. This is because the 4s orbital is the outer orbital, even though it is filled up before the 3d orbital. I hope this helps.

[Anne Cam 3A]

4s electrons are lost first only from group 1 and 2 metals like K and Ca, because there are no electrons in 3d orbitals. But with d-block transition metals, as the 3d orbitals gain electrons they become lower energy than 4s.

Cr is [Ar]3d⁵4s¹ and Cu is [Ar]3d¹⁰4s¹ because they are more stable with half-filled and filled 3d orbitals, respectively. They are not exceptions to losing 4s electrons; because the 4s orbital is the outermost one (just like it is for other d-block metals), it would lose electrons first as well. So Cu⁺ would be [Ar]3d¹⁰.

[Bella Fuentes 1D]

Is it always necessary to eliminate the amount of valence electrons to maintain the elements ionization in the electron configuration?

[Chem_Mod]

I am not sure by what you are trying to ask. To get the ion's electron configuration, write the electron configuration for the atom and then remove/add the necessary number of electrons to the next highest/lowest orbital.