Question

Most paints contain compounds of transition elements. What do you think it is?​

Answer 1

Answer:

The reason why transition metal in particular are colorful is because they have unfilled or either half filled d orbitals. There is Crystal field theory which explains the splitting of the d orbital, which splits the d orbital to a higher and lower orbital. Now, the electrons of the transition metal can "jump".

Explanation:

Answer 2

A simple explanation would be to know first what causes "color". The key principle is "electronic transition". To have an electronic transition, an electron must "jump" from a lower level to a higher level orbital. Now, light is energy right? So, when there is light, we see colors. But it doesn't stop there. The reason why transition metal in particular are colorful is because they have unfilled or either half filled d orbitals.

There is Crystal field theory which explains the splitting of the d orbital, which splits the d orbital to a higher and lower orbital. Now, the electrons of the transition metal can "jump". Note that light is absorb for electrons to "jump", but this electrons will fall eventually back again to its ground state, releasing light of specific intensity and wavelength. We perceive this as colors.

Now for the fun part. Note that electron can't transition if an orbital is already full. Take a look of Zinc in your periodic table. Note that a d orbital can only hold up to 10 electrons. Notice that zinc has 10 electrons in its d orbital. Yes, you guess it right, it will not color and is not consider a transition metal. zinc is not a transition metal but it is part of the d-block elements. Mind blown!