a) 2 atoms . so if you do 2 out of 100 it will be 2%. plus the hydrogen 4% = 6% b) 1 atom so 1% . plus the hydrogen 3% = 4% c) 2 atoms so 2% . plus the oxygen 4% = 6% d) 1 atom so 1% . plus sodium 1% plus oxygen 3% = 5% so the compound with the greatest percentage is a & c
idk if this is right i haven’t learnt this in school i googled this