1. Sulfite   S   SO3   Br   O   Hint Half-n-half Clue   2. Bisulfate or Hydrogen sulfate   Br   I   HSO4   Cl   Half-n-half Clue   3. Carbonate   CO3   HSO4   HSO3   Cl   Half-n-half Clue   4. Sulfide   Br   S   CO3   HCO3   Half-n-half Clue   5. Sulfate   SO4   Br   PO4   S   Half-n-half Clue   6. Iodide   I   S   SO3   O   Half-n-half Clue   7. Phosphate   O   CO3   PO4   HCO3   Half-n-half Clue