Final answer:
The polyatomic ion with a 3- ionic charge from the given options is phosphate (PO4⁻³).
Step-by-step explanation:
The polyatomic ion with a 3- ionic charge among the options provided is phosphate (PO43-). Hydrogen carbonate (HCO3-), hydroxide (OH-), nitrate (NO3-), and sulfate (SO42-) have ionic charges of -1 and -2 respectively. Phosphate, with the formula PO43-, is the correct answer because it is the only ion among the list that carries a 3- charge.