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)

KFKF

NaNa22OO

MgOMgO

AlAl22OO33

CaBrCaBr22

CsICsI

ZnIZnI22

AgAg22SS

POLYATOMIC IONSPOLYATOMIC 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

SOSO442-2- CO CO33

2-2- PO PO443-3- OH OH--

(SO(SO442-2- (CO (CO33

2-2- (PO (PO443-3- (OH (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 polyatomicsFormulas 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)Al(SCN)33

Try a few more:

• Na+1 and OH-1

• K +1 and HCO3-1

• Mg+2 and CO3-2

• Li +1 and NO3-1

• Ca+2 and SO4-2

NaOHNaOH

KHCOKHCO33

MgCOMgCO33

LiNOLiNO33

CaSOCaSO44

These are more challenging:

• Mg+2 and (PO4)-3

• Al+3 and (NO3)-1

• Fe+2 and OH-1

• Hg2+2 and SCN-1

• Mg+2 and HCO3-

• Al+3 and C2O42-

MgMg33(PO(PO44))22

Al(NOAl(NO33))33

Fe(OH)Fe(OH)22

HgHg22(SCN)(SCN)22

Mg(HCOMg(HCO33))22

AlAl22(C(C22OO44))33

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(NOZn(NO33))22

Mg(OH)Mg(OH)22

LiLi22COCO33

KK22SOSO44

CaCa33(PO(PO44))22

Be (ClOBe (ClO33))22