total 5 atoms
2 of Mg and 3 of O
one atom
NO2 = 3 atoms.
4
There is no CuSO. If you mean CuSO4, it would be 6 atoms per formula unit; one Cu atom, one S atom, and 4 O atoms.
2H +1S +4O = 7
One you idiot it's an element Au
Borax (Na2B4O7) has two sodium atoms in the formula unit.
Cl2 is a molecule formed of 2 atoms of Chlorine.
Sodium oxide is made up of three atoms: two sodium atoms and one oxygen atom.
Sand is silicon dioxide, formula SiO2
It takes three helium atoms to create one carbon atom through nuclear fusion in stars.
Silicon dioxide is a molecule made of one silicon and two oxygen for a total of three atoms.