UNIT 6 BONDING AND UNIT 6 BONDING AND NOMENCLATURENOMENCLATURE

LESSON 3LESSON 3

NAMING COMPOUNDSNAMING COMPOUNDS

Chemist name compounds Chemist name compounds according to the atoms and bonds according to the atoms and bonds that compose the compound.that compose the compound.

NAMING COMPOUNDSNAMING COMPOUNDS

Naming Ionic CompoundsNaming Ionic CompoundsNaming Ionic CompoundsNaming Ionic Compounds

Name the cation first, then anionName the cation first, then anion

Monatomic cation = name of the Monatomic cation = name of the elementelement

CaCa2+2+ = calcium = calcium

Monatomic anion = root + -ideMonatomic anion = root + -ide

ClCl = chlor = chlorideide

CaClCaCl22 = calcium chloride = calcium chloride

Naming Ionic CompoundsNaming Ionic CompoundsNaming Ionic CompoundsNaming Ionic Compounds

some some metals can form more than one metals can form more than one charge (usually the transition metals)charge (usually the transition metals)

use a use a Roman numeralRoman numeral in their name:in their name:

PbClPbCl22 – use the – use the anionanion to find the charge to find the charge

on the cation (chloride is always 1-)on the cation (chloride is always 1-)

PbPb2+2+ is the lead (II) cationis the lead (II) cation

PbClPbCl22 = lead ( = lead (IIII) chloride) chloride

(Metals with multiple oxidation states)(Metals with multiple oxidation states)

Practice by writing the formula Practice by writing the formula or name as required…or name as required…

Iron (II) PhosphateIron (II) PhosphateTin (II) FluorideTin (II) Fluoride

(sometimes called Stannous)(sometimes called Stannous)

Potassium SulfidePotassium SulfideAmmonium ChromateAmmonium Chromate

MgSOMgSO44

FeClFeCl33

Practice by naming compundPractice by naming compund

MgSOMgSO44

FeClFeCl33

Naming and Writing Formulas Naming and Writing Formulas for Molecular Compoundsfor Molecular Compounds

Molecular compounds are…Molecular compounds are…made of just made of just nonmetalsnonmetals

smallest piece is a smallest piece is a moleculemolecule

can’t be held together by opposite can’t be held together by opposite charge attractioncharge attraction

can’t use charges to figure out how can’t use charges to figure out how many of each atom(there are no many of each atom(there are no charges)charges)

Molecular compounds - Formulas are Molecular compounds - Formulas are easy!easy!

Molecular compoundsMolecular compounds: the : the name name tells youtells you the number of atoms. the number of atoms.

– Uses Uses prefixesprefixes to tell you the exact to tell you the exact number of each element present!number of each element present!

PrefixesPrefixes 1 = mono-1 = mono-

2 = di-2 = di-

3 = tri-3 = tri-

4 = tetra-4 = tetra-

5 = penta-5 = penta-

6 = hexa-6 = hexa-

7 = hepta-7 = hepta-

8 = octa- 8 = octa-

9 = nona-9 = nona-

10 = deca-10 = deca-

Write formulas for these:Write formulas for these:diphosphorus pentoxidediphosphorus pentoxide

tetraiodine nonoxidetetraiodine nonoxide

sulfur hexafluoridesulfur hexafluoride

nitrogen trioxidenitrogen trioxide

carbon tetrahydridecarbon tetrahydride

phosphorus trifluoridephosphorus trifluoride

aluminum chloridealuminum chloride (Ionic compound)

Naming Molecular CompoundsNaming Molecular Compounds

To write the name:To write the name:

1. 11. 1stst element: Prefix +name (least element: Prefix +name (least electronegative).electronegative).

2. 22. 2ndnd element: Prefix +name (more element: Prefix +name (more electronegative) change ending electronegative) change ending to -ideto -ide

One exception - we One exception - we don’tdon’t write write monomono if there if there is only one of the first element.is only one of the first element.

Normally, we do not have double vowels when Normally, we do not have double vowels when writing names (oa oo)writing names (oa oo)

Practice by naming these:Practice by naming these:

NN22OO

NONO22

ClCl22OO77

CBrCBr44

COCO22

BaClBaCl22 (This one will not use prefixes, since it is an ionic compound!)

= dinitrogen monoxide(also called nitrous oxide or laughing gas)

= nitrogen dioxide

= dichlorine heptoxide

= carbon tetrabromide= carbon dioxide

Naming HydratesNaming Hydrates

Naming HydratesNaming Hydrates

Hydrates are ionic compounds that Hydrates are ionic compounds that absorb water into their solid absorb water into their solid structures.structures.Anhydrous are ionic compounds that Anhydrous are ionic compounds that are free of water.are free of water.The name of the hydrated compound The name of the hydrated compound must reflect how many water must reflect how many water molecules are attached (use prefixes)molecules are attached (use prefixes)

Practice Naming HydratesPractice Naming Hydrates

CuSOCuSO44 ● 5H● 5H22OO

Copper II Sulfate pentahydrateCopper II Sulfate pentahydrate

Fe POFe PO44 ● 4H● 4H22OO

Iron III Phosphate tetrahydrateIron III Phosphate tetrahydrate

Helpful to remember...Helpful to remember...1. In an ionic compound, the net ionic 1. In an ionic compound, the net ionic

charge is charge is zero zero (criss-cross method)(criss-cross method)

2. An 2. An -ide-ide ending generally indicates a ending generally indicates a binary compoundbinary compound

3. An 3. An -ite-ite or or -ate-ate ending means there is ending means there is a polyatomic ion that has oxygena polyatomic ion that has oxygen

4. 4. PrefixesPrefixes generally mean molecular; generally mean molecular; they show the number of each atomthey show the number of each atom

Helpful to remember...Helpful to remember...

5. A 5. A Roman numeralRoman numeral after the after the name of a cation is the name of a cation is the ionic ionic chargecharge of the cation of the cation