First off, how do you eve find out if it would be colored or colorless? Will aqueous solutions of the following salts be colored or colorless? Explain.

Question

a. Titanium (II) chloride
b. Beryllium chloride
c. Tin (II) nitrate
d. Iron (III) nitrate

Answer 1

Look at the unpaired electrons, especially those in the d orbitals. Unpaired electrons usually mean color. TiCl2, for example, we would expect to be colored.
Ti-22 is 1s2 2s2 2p6 3s2 3p6 3d2 4s2.
If we make the Ti^2+ ion to form TiCl2, then remove the 2 4s electrons and we have 1s2 2s2.......3d2. All of those electrons are paired EXCEPT 3d2. Both of those are unpaired so Ti^2+ solutions usually are colored. How do you know they are unpaired. Remember there are 5 3d orbital and those 5 orbitals can hold 2 electrons each to make a total of 10. Remember, too, that Hund's rule says that the electrons will be unpaired until they MUST pair up. So all of those elements in the 3d series will be colored if they have 3d electrons until Zn in which the last electron goes in to pair up and most Zn salts are not colored.