What does this property of transition metals mean? [duplicate]








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[Which electrons will be taken when oxidations take place and how does the resulting orbital diagram look like?](/questions/19749/which-electrons-will-be-taken-when-oxidations-take-place-and-how-does-the-result)

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what does it mean:


"Transition metals either have incompletely filled d subshells or readily give rise to cations that have incompletely filled d subshells.


I don't understand the portion starting from " or readily give rise to..."




Take the electronic configuration of copper (atomic number $29$) $\ce{[Ar] 3d^10 4s^1}$. According to the first portion of the definition, copper doesn't have incompletely filled subshells. But, copper readily gives rise to cation $\ce{Cu^{2+}}$ that has the electronic configuration $\ce{[Ar] 3d^9 4s^0}$ with incompletely filled d subshells. So, copper is considered as a transition metal.


Now, you can guess why zinc (atomic number $30$) is not considered as a transition metal.


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