What controls the electrical properties of the atom? the valence electron is referred to as a ? when silicon atoms combine to form a solid, they arrange themselves into an orderly pattern called ?

It is the valence orbit that controls the electrical properties of the atom. The valence electron is referred to as a "free electron.' Valence electrons have the highest energy of all electrons in an atom; they are also the most reactive, meaning they are usually the electrons involved in bonding. When silicon atoms combine to form a solid, they arrange themselves into an orderly pattern called a crystal.

Yes it would be a physical change.