Answer:
A Calcium is in group 2
explanation:
because it forms only the Ca 2+ ion. B Dihydrogen phosphate is the H 2PO 4 − ion (Table 2.4 "Common Polyatomic Ions and Their Names"). Two H 2PO 4 − ions are needed to balance the positive charge on Ca 2+, to give Ca(H 2PO 4) 2.
