How you would name the molecule N2O4?

The molecule ##N_2O_4## would be dinitrogen tetroxide.

For molecular (covalent) the name is determined by the numeric prefixes based upon the number of atoms of each element in the molecule.

mono = 1 di =2 tri = 3 tetra = 4 (If you play Tetris, four blocks for each piece) penta = 5 hexa = 6 hepta = 7 octa = 8 nona = 9 deca = 10

The "a" at the end of the prefix is dropped if the next letter is an "o". Thus the name is "tetroxide", not "tetraoxide".

The molecule ammonia ##NH_3## is nitrogen trihydride.

I hope this was helpful. SMARTERTEACHER