Question

iond of zn2+ and ti4+ are colourless while cu2+ and ni2+ are coloured . why ?​

Answer 1

Answer:

Cu2+ has an unpaired electron (its configuration is [Ar] 3d9), whereas Zn2+ has all paired electrons (configuration [Ar] 3d10). ... Also, the unpaired electron in the copper ion allows electron transition in the visible region to take place, so the ion is coloured...