Answer:
Explanation:
Take out your periodic table.
The choices that have one 1 member of the periodic table on it are elements.
He is the symbol for Helium
O2 oxygen
C3 but this is really odd. It is Carbon but Carbon usually does not combine in 3s.
The rest are all compounds (they are made up of the elements on the periodic table). For example
H2SO4
is made up of 2 Hydrogens
1 sulfur
4 oxygens.
All the others do exactly the same thing.
