Topic: Polyatomic Ions Do Now: Review, write the binary ionic formula for: Potassium (K) and Fluorine (F) Zinc (Zn) and Iodine (I) Sodium (Na) and Oxygen (O) Magnesium (Mg) and Oxygen (O) Aluminum (Al) and Oxygen (O) Calcium (Ca) and Bromine (Br) Cesium (Cs) and Iodine (I) Silver (Ag) and Sulfur (S) KF Na 2 O MgO Al 2 O 3 CaBr 2 CsI ZnI 2 Ag 2 S

POLYATOMIC IONS group of covalently bonded atoms that have a charge Table E: (+)’ve or (–)’ve polyatomic ions have “names” (-) polyatomic ions can form ionic bonds with (+) metal ions SO 4 2- CO 3 2- PO 4 3- OH - (SO 4 2- (CO 3 2- (PO 4 3- (OH -

Ternary Compounds contain 3 or more elements usually contain a polyatomic ion Look at table E – who would be bonded to what?!!!?

Formulas with polyatomics What’s the formula for the compound formed from Al and SCN? The charges must add up to zero, so write the symbols, positive first! Al(SCN) 3

Try a few more: Na +1 and OH -1 K +1 and HCO 3 -1 Mg +2 and CO 3 -2 Li +1 and NO 3 -1 Ca +2 and SO 4 -2 NaOH KHCO 3 MgCO 3 LiNO 3 CaSO 4

These are more challenging: Mg +2 and (PO 4 ) -3 Al +3 and (NO 3 ) -1 Fe +2 and OH -1 Hg 2 +2 and SCN -1 Mg +2 and HCO 3 - Al +3 and C 2 O 4 2- Mg 3 (PO 4 ) 2 Al(NO 3 ) 3 Fe(OH) 2 Hg 2 (SCN) 2 Mg(HCO 3 ) 2 Al 2 (C 2 O 4 ) 3

Some of the most challenging are Zinc + Nitrate ion Magnesium + Hydroxide ion Lithium + Carbonate ion Potassium + Sulfate ion Calcium + Phosphate ion Beryllium + Chlorate ion Zn(NO 3 ) 2 Mg(OH) 2 Li 2 CO 3 K 2 SO 4 Ca 3 (PO 4 ) 2 Be (ClO 3 ) 2