How many atoms of oxygen are in one formula unit of al2(so4)3

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

What is the maximum number of electrons that an atomic orbital can contain?

The number of neutrons is equal to the atomic number minus the atomic mass. a. true b. false