posted by Catherine .
Which of the following transition metal ions has a color? Cr3+ , hg2+, v2+ How can you predict that? I don't understand!!
Colored compounds often result from unpaired electrons.
Cr (the metal, not the ion) has
1s2 2s2 2o6 3s2 3p6 3d5 4S1
Take away the last three electrons and you are left with
1s2 2s2 2p6 3s2 3p6 3d3. You can see that with the transition elements you need not worry about anything but the 3d and 4s levels.So Cr^3+ has a 3d3 configuration which means 3 unpaired electrons and color.
^^ that's wrong .-.
Of its a bean thema its in between If ur a white shut the door