CuF 2

The d -block elements form coloured compounds. These compounds have ions with unpaired electron in d-subshell.

i) Na and Mg belong to s -block , so NaCl and MgCl 2 are colourless compounds.

ii) CuF 2

Oxidation state of Cu in CuF 2 is +2

Cu 2+ =ls 2 ,2s 2 ,2p 6 ,3s 2 ,3p 6 ,4s°,3d 9

in which Cu has one upaired electron is coloured

iii) CuI

Oxidation state of Cu in CuI = +1

Cu + =1s 2 2 s 2 2p 6 ,3s 2 ,3p 6 ,4s°,3d 10

It has no unpaired electron. So, Cul is colourless.

Only CuF 2 is coloured among given choices.