Introduction to Bonding

C. Johannesson I II III IV

Chemical Bonding

Introduction to Bonding

C. Johannesson

Vocabulary

Ionan atom or group of atoms that carries an electrical charge

Ionic Compounda compound that results from a transfer of electrons from one element to another

C. Johannesson

Vocabulary

Chemical Bond• attractive force between atoms or ions

that binds them together as a unit

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

C. Johannesson

Vocabulary

CHEMICAL FORMULA

MolecularFormula

FormulaUnit

IONIC COVALENT

CO2NaCl

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Vocabulary

COMPOUND

TernaryCompound

BinaryCompound

2 elements more than 2elements

NaNO3NaCl

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Vocabulary

ION

PolyatomicIon

MonatomicIon

1 atom 2 or more atoms

NO3-Na+

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IONIC COVALENTBond FormationType of Structure

Solubility in WaterElectrical ConductivityOtherProperties

e- are transferred from metal to nonmetal

high

yes (solution or liquid)

yes

e- are shared between two nonmetals

low

no

usually not

MeltingPoint

crystal lattice true molecules

Types of Bonds

Physical State solid liquid or gas

odorous

C. Johannesson

“electron sea”

METALLICBond FormationType of Structure

Solubility in WaterElectrical ConductivityOtherProperties

MeltingPoint

Types of Bonds

Physical State

e- are delocalized among metal atoms

very high

yes (any form)

no

malleable, ductile, lustrous

solid

C. Johannesson

C. Johannesson

Bond Polarity• Most bonds are

a blend of ionic and covalent characteristics.

• Difference in electronegativity determines bond type.

C. Johannesson

Bond Polarity

Electronegativity• Attraction an atom has for a shared pair

of electrons.• higher e- neg atom -

• lower e- neg atom +

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Bond Polarity

Electronegativity Trend• Increases up and to the right.

C. Johannesson

Nonpolar Covalent Bond• e- are shared equally• symmetrical e- density• usually identical atoms

Bond Polarity

C. Johannesson

+ -

Bond Polarity

Polar Covalent Bond• e- are shared unequally• asymmetrical e- density• results in partial charges (dipole)

C. Johannesson

• Nonpolar

• Polar

• Ionic

View Bonding Animations.

Bond Polarity

C. Johannesson

Bond Polarity

Examples:• Cl2

• HCl

• NaCl

3.0-3.0=0.0Nonpolar

3.0-2.1=0.9Polar

3.0-0.9=2.1Ionic