POLYATOMIC IONS tightly bound groups of atoms that behave as a unit and carry a charge most end in –ite or –ate exceptions: NH4+ – ammonium CN– – cyanide OH– – hydroxide

POLYATOMIC IONS

–ATE vs. –ITE phosphate vs. phosphite PO43- PO33- –ate = one more oxygen than –ite charge is the same

Formula Name 1– H2PO4– dihydrogen phosphate 2– HPO42– hydrogen C2H3O2 – acetate phosphate HSO3– hydrogen sulfite C2O42– oxalate HSO4– hydrogen sulfate SO32– sulfite HCO3– hydrogen carbonate SO42– sulfate NO2– nitrite CO32– carbonate NO3– nitrate CrO42– chromate CN– cyanide Cr2O72– dichromate OH– hydroxide SiO32– silicate MnO4– permanganate 3– PO43– ClO– hypochlorite PO33– phosphite ClO2– chlorite ClO3– chlorate 1+ NH4+ ammonium ClO4– perchlorate

POLYATOMIC IONS when a polyatomic ion begins with H, it is H+ + another polyatomic ion: HCO3– is H+ and CO32– HPO42– is H+ and PO43–

TERNARY IONIC COMPOUNDS contain three different elements usually contain a polyatomic ion balance the charge like a binary compound – treat the polyatomic ion as single unit

TERNARY IONIC COMPOUNDS calcium carbonate Ca2+ CO32- Ca2(CO3)2 reduce: CaCO3 lithium carbonate Li+ CO32- Li2CO3

TERNARY IONIC COMPOUNDS magnesium hydroxide Mg2+ OH- Mg(OH)2 sodium phosphite Na+ PO33- Na3PO3

TERNARY IONIC COMPOUNDS Al3+ OH– Al(OH)3 aluminum hydroxide Sn2+ PO43– Sn3(PO4)2 tin(II)phosphate (stannous) Na+ CrO42– Na2CrO4 sodium chromate K+ MnO4– KMnO4 potassium permanganate

TERNARY IONIC COMPOUNDS calcium oxalate Ca2+ C2O42- CaC2O4 potassium dichromate K+ Cr2O72- K2Cr2O7 chromic sulfite Cr3+ SO33- CrSO3 lead (IV) acetate Pb4+ C2H3O2- Pb(C2H3O2)4