On what ground can you say that scandium `(Z=21)` is a transition element but zinc `(Z=30)` is not?

Explanation

E.C. of `""_21Sc = 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(1)4s^(2)` . In this E.C 3d orbital have one electron in its ground state. That is why it is regarded as a transition element
E.C of `Zn = 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(2)`
Zn does not have partly filled .d. orbital in its ground state or in its excited state that is why it is not considered as a typical transition element.