Question

zn is diamagnetic whereas cu is paramagnetic why??

Answer 1

Zn(30) = (Ar) 3d10 4s²

Cu (29) = (Ar) 3d10 4s1

When we fill up electrons in orbital we find that zinc are completely paired while copper has one unpaired electron in 4s orbit. So, that becomes the reason for diamagnetic character in zinc and paramagnetic character in copper. Unpaired electrons indicated paramagnetic character and are colorful while paired electrons indicate diamagnetic character and are colourless