How can we relate the presence if color in an ionic solution as a characteristic lf electron configuration

Colours come from electrons moving between shells. The energy of light matches the energy gaps between electron shells.
Explanation:
Electrons are arranged in energy levels (shells) and there are energy gaps between shells. Electrons must be in one shell and cannot be in between. Electrons can move from one shell to another in the right conditions.
When an atoms absorbs energy from heat or light, the atom starts to move a little faster, in other words, it gets warmer. If the energy absorbed is just right to match the energy gap between shells, electrons can jump from one shell to another.
If an object is red, then the energy between gaps during light absorption is equal to the energy of the complementary light color, green.
If the object emits red light, then the energy between gaps during light emission is equal to the energy of red light.

The mass has escaped into a gas which you can not see so the law stays true.

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