Ionic Bonding and Compounds

Naming & Formula Writing

Created by P. Perkerson

Monatomic Ions

Charged particles composed of one type of atom

Cations (+) or anions (-) atoms lose or gain electrons to become stable

Oppositely charged ions are attracted to each other and form an ionic bond

Ex. Na+ Cl- form NaCl

Binary Compounds

Composed of a cation and an anion Metal and a nonmetal Neutral (total + and – charges

cancel) Use subscripts to make charges = 0 Ions are in smallest whole # ratio Naming – cation first (name of

metal), anion second (name of nonmetal with an “ide” ending

Binary Examples

Lithium and oxygen Li+ O2- forms Li2O Lithium oxide

Magnesium and sulfur Mg2+ S2- forms MgS Magnesium sulfide

Try the criss cross method!

If the charges equal zero, no subscripts are required.

If they don’t equal zero, use subscripts to make the total charge zero.

Strontium and phosphorus Sr2+ P3-

Sr3P2 Strontium phosphide

You try it!

Potassium and bromine KBr potassium bromide Calcium and phosphorus Ca3P2 calcium phosphide Aluminum and chlorine AlCl3 aluminum chloride Sodium and nitrogen Na3N sodium nitride

Characteristics of Ionic Compounds

Electrically neutral as solids High melting point Brittle solids Water soluble Solutions are good electrical

conductors

Binary Compounds with Transition Metals

Transition metals may have more than one charge

When naming, must indicate charge with a Roman Numeral – look at what it is bonded with to determine

Ex. CuCl2 copper (II) chloride CuCl copper (I) chloride

Formula Writing with Transitions

The Roman numeral in the name tells the charge of the transition metal.

Ex. Chromium (III) oxide Cr2O3 Exceptions: Zn & Cd are always 2+

and silver is always 1+ so no Roman numeral is used

Other Exceptions

Lead and Tin are not transition metals but they act like them – can have more than one charge.

Therefore, a Roman numeral is used when naming ionic compounds containing them.

SnO2 tin (IV) oxide

Now you try it!

Iron (III) oxide Fe2O3 Nickel (II) nitride Ni3N2 Cu2S Copper (I) sulfide Co3P2 Cobalt (II) phosphide

STOP!!! DON’T GO ANY FURTHER!!

REALLY!! YOU ARE DONE – NO MORE!!

Tertiary Ionic Compounds

Composed of either a cation or anion and a polyatomic ion

Polyatomic ions are covalently bonded atoms that behave as a charged particle. (most are anions)

When naming, use same naming rules except give the polyatomic its same name

Tertiary Example

Calcium and phosphate Ca2+ PO4

3- form Ca3(PO4)2 Calcium phosphate Note that when more than one of a

polyatomic ion is required in the formula, the PAI is in () with the subscript outside the ()

Try these!

Aluminum and acetate Al(C2H3O2)3 Magnesium and sulfate MgSO4 Copper (II) phosphate Cu3(PO4)2 Iron (II) carbonate FeCO3 Ammonium and nitrite NH4NO2 Nickel (II) hydroxide Ni(OH)2