Answer:
The symbols of the elements and subscripts are used to represent a molecule of an element or a compound.
N2, O2, H2, Cl2, Br2, I2, F2, At2 are diatomic molecules of the element in each formula.
C6H12O6, NO2, H2O, CO2 are examples of molecular compounds.
NaCl, MgSO4, CaCl2 are examples of ionic compounds.