Question

why
Cu2+ ion is paramagnetic while Zn2+ is diamagnetic?​

Answer 1

Cu2+ has an unpaired electron (its configuration is [Ar] 3d9), whereas Zn2+ has all paired electrons (configuration [Ar] 3d10). Pairing electrons leads to diamagnetism, and unpaired electrons leads to paramagnetism.

Answer 2

Answer:

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Cu2+ has an unpaired electron (its configuration is [Ar] 3d9), whereas Zn2+ has all paired electrons (configuration [Ar] 3d10). Pairing electrons leads to diamagnetism, and unpaired electrons leads to paramagnetism.