The reason behind that is because Sulfur's symbol is S, and Oxide means oxygen, but since we have the word tri before that, we can conclude that tri means 3, and that means their are 3 oxygen's.
So our SO3
Answer from: Quest
the link still does not work even when adding it to the url bar
Covalent bonds generally form when the bonded elements have a difference in electronegativity less than 1.5. subtract the electronegativities for the following pairs of elements and predict whether they form a covalent bond. electronegativity difference of c and c: ionic covalent electronegativity difference of mg and cl: ionic covalent