I II III IV

Chemical Bonding

Chapter 7

Section 1

Pages 219-231

Chemical Formulas

Chemical formulas indicate the elements involved and how many of each type are in the molecule.

C8H18 Al2(SO4)3

subscripts

Types of Ions

Monatomic Ions – one element

Criss-Cross Method

Used to write formulas of ionic compounds (salts)

Step 1: List Charges of each ionStep 2: Criss-Cross the # of the Charge only!

Step 3: Simplify (Never write a subscript of 1)

Criss-Cross means: • # of the Charge of cation subscript of the anion.• # of the Charge of anion subscript of the cation.

Types of Ions

Polyatomic – more than one element

Example: Calcium Phosphate

Ca = PO4 = 2+ 3-

Use parentheses for a polyatomic ion.

Ca (PO4)

23

Empirical Formula

Lowest Whole Number Ratio of Elements

CaSO4 = 1 calcium ion for every 1 sulfate ion

Na2SO4= 2 sodium ions for every 1 sulfate ion

*Stock System of Naming Compounds

Roman numeral matching the charge is used.

Ex: Cu +1, copper I

Cu +2, copper II

Cu+2 N03-: Cu(N03)2 copper II nitrate

Cu+ NO3- : CuNO3 copper I nitrate

Naming Binary Ionic Compounds

Cation: Name the Metal (use Roman numerals for transition metals)

Anion: nonmetal Change the ending to –ide.

Calcium Chloride

Barium Oxide

Potassium Sulfide

Iron (III) Bromide

Chromium (III) Oxide

Traditional Naming of Ionic Compounds

Traditional naming of ionic compounds used the Latin names or some common names and a suffix corresponding to the charge as follows.

Copper: Cuprum

Cu+1: cuprous Cu+2: cupric

The ous ending was used with the lower charged ion.

The ic ending was used with the higher charged ion.

Tradition Names

Ferrous Nitrate : Iron +2, nitrate: Fe(NO3)2

Plumbic Chloride: Lead +4, chlorine: PbCl4Latin Names:

Ferrum – Iron, Cuprum – Copper,

Stannum – Tin, Mercurum – Mercury

Common Names: Any element with more than one possible charge: lead, mercury, tin, etc.

*Examples of Naming for Polyatomic Ions

Calcium Sulfite

Barium Phosphate

Ammonium Sulfide

Iron (III) Sulfite

Naming Molecular Compounds

Same rules

EXCEPT

include prefixes

NEVER start a

compound name

with mono-

(drop the prefix)

1 = mono 2 = di

3 = tri 4 = tetra

5 = penta 6 = hexa

7 = hepta 8 = octa

9 = nona 10 = deca

Naming Molecular Compounds

NO2= nitrogen dioxide

BF3= boron trifluoride

P2O5= diphosphorus pentoxide

*Molecular Formula

Indicates how many atoms are in a

single molecule of the compound.

C6H12O6 = glucose

6 carbon atoms

12 hydrogen atoms

6 oxygen atoms

Naming of Acids & Salts

Binary Acids: Contain only two elements. Hydrogen & a nonmetal Hydro- ____________ -ic acid.

Ex: HCl = Hydrochloric Acid

H2S = Hydrosulfuric Acid

Naming of Acids & Salts

Binary Salts: Contain only two elements. A metal & a nonmetal Name the metal & change the ending on the

non-metal to –ide.

Ex: NaCl = Sodium Chloride

MgBr2 = Magnesium Bromide

Naming of Acids & Salts

Ternary Acids: Prefix & Suffix X could be any element other than (Sulfur,

Phosphorus, Nitrogen or Carbon)

HXO = hypo-________-ous HXO2 = __________-ous

HXO3 = __________-ic

HXO4 = per-_________-ic

Naming of Acids & Salts

Example:

HClO = hypochlorous acid HClO2 = chlorous acid

HClO3 = chloric acid

HClO4 = perchloric

Naming of Acids & Salts

Ternary Salts: Prefix & Suffix X could be any element other than (Sulfur,

Phosphorus, Nitrogen or Carbon)

XO- = hypo-________-ite XO2

- = __________-ite

XO3 - = __________-ate

XO4 - = per-_________-ate

Naming of Acids & Salts

Example; Chlorine (X represents any

metal) XClO- = hypochlorite XClO2

- = chlorite

XClO3 - = chlorate

XClO4 - = perchlorate