I II III IV

Chemical Bonding

IonicBonding

Valence Electrons

Valence Electrons – outer energy level

electrons involved in bonding

12 63 4 75

8

Lewis Structures

Electron Dot Diagrams show valence e- as dots distribute dots like arrows

in an orbital diagram 4 sides = 1 s-orbital, 3 p-orbitals EX: oxygen

2s 2pO

X

Lewis Structures

Octet Rule Most atoms form bonds in order to obtain 8 valence

e-

Full energy level = stability ~ Noble Gases

Ne

Chemical Bonds

Why do chemical bonds form?

attractive force between atoms or ions binds them together as a unit

bonds form in order to…decrease potential energy (PE)increase stability

Properties of Ionic Compounds

Bond Formation Electrons are transferred from metal to nonmetal

Type of Structure Crystal Lattice

Physical State Solid

Melting Point High

Solubility in Water Yes

Electrical Conductivity Yes

Lewis Structures

Ionic Bonding – Electrons are transferred

from the metal atom to the nonmetal atom.

Lewis Structures

Ionic – the arrow shows the transfer of e-

Vocabulary

CHEMICAL FORMULA

FormulaUnit

IONIC

NaClNaCl

Vocabulary

COMPOUND

TernaryCompound

BinaryCompound

2 elementsmore than 2

elements

NaNONaNO33NaClNaCl

Vocabulary

ION

PolyatomicIon

MonatomicIon

1 atom 2 or more atoms

NONO33--NaNa++

1+

2+ 3+ 4+/4- 3- 2- 1-

0

Common Ion Charges

Also called Oxidation Numbers

Common Ion Charges

What do the common ion charges tell you?

The number of electrons that are either lost/gained or transferred in order to form an ionic bond.

For example: Na has a charge of +1, this means that Na will lose or transfer one electron to the non-metal ion when bonding.

When bonding, will the following atoms lose

or gain electrons? How many?

Potassium OxygenFluorineCalcium

Lose 1

Gain 2

Gain 1

Lose 2

Ionic Nomenclature

Writing Ionic Formulas

Write the cation first then the anion. Don’t show charges in the final formula.

Overall charge must equal zero. If charges cancel, just write symbols. If not, use subscripts to balance charges.

potassium chloride

magnesium oxide

Calcium fluoride

K+ Cl

Mg2+ O2

Ca2+ Fl

KCl

MgO

CaFl2

Ionic Nomenclature

Ionic Nomenclature

Writing Names of Ionic Compounds

Write the names of the cation first.

Change ending of the anion to -ide.

NaBr

K2S

CaI2

sodium bromide

Potassium sulfide

Calcium iodide

Ionic Nomenclature

Ionic Nomenclature

More on writing Names of Ionic Compounds

Polyatomic ions have special names.

Stock System - Use Roman numerals to show the ion’s charge for transition metals. Overall charge must equal zero.

NaNO3

K2SO4

NH4NO3

sodium nitrate

Potassium sulfate

Ammonium nitrate

Ionic Nomenclature

Fe2S

CuSO4

CoCl2

Iron(I)sulfide

Copper(II)sulfate

Cobalt(II)chloride

Ionic Nomenclature