Simplify the following text for a Grade 9 native English-speaking person.
Original: Tellurium makes chemical compounds in several oxidation states : -2 , +2 , +4 , and +6 .
Simplified: Tellurium and selenium compounds are similar . It exhibits the oxidation states â ' 2 , +2 , +4 and +6 , with the +4 state being most common .