All the elements on the periodic table start with a capital letter and only some of them have a second letter that is lower case. So if you see two capital letters together in a ion then you will know that it is a polyatomic.
Answer: All the elements on the periodic table start with a capital letter and only some of them have a second letter that is lower case. So if you see two capital letters together in a ion then you will know that it is a polyatomic.
