Microscropic World I

Chemical Bonding

Ionic bonding

Nature of Force: Electrostatic Attraction

Compounds of metal& non-metal

Non-directional

Forces between cations& anions

Ions:

New node

atom(s) that have an overall charge

Eg. NaCl

Metallic bonding

Nature of Force: Electrostatic Attraction

Between cations& delocalized e-

Non-directional

Forces between metals

Eg. Na metal

Covalent bonding

Nature of Force: Electrostatic Attraction

Found only in non-metals

Molecules:

smallest part of element/compound, exist on its own under normal conditions

Forces between nuclei& shared e-

Directional

Eg.NH3

Dative covalent bond

Both e- of shared pair contributed by same atom

Atoms

Protons

+charge

atomic no.

Neutrons

neutral

mass no.-atomic no.

e-

-ive charge

Isotopes

diff atoms of same element

same no. of p, diff no. of n

Structure& properties

Periodic Table

Period no.

no. of occupied e- shells

Group no.

no. of e- in outermost shell

determine chemical prop.

Group I, II

Reactivity ↑ down the group

Group VII, VIII

Reactivity ↓ down the group

Physical Properties

m.p.

Requirement of energy

Break pattern of particles in solid to random arrangement in liquid

b.p.

Requirement of energy

Separate particle in solid to widely separated particles in gases

Hardness

Ease to deform arrangement of particles in solid when stress is applied

Conductivity

Present of mobile ions

Solubility

Soluble

New interaction formed stronger than old interaction broken

Insoluble

New interaction formed weaker than old interaction broken

Structure

Giant Structure

Giant ionic bond

High b.p.& m.p.

Hard

Lots of energy required to break ionic bonds

X conduct electricity in solid state

X mobile ions

Conduct electricity in molten state

Mobile ions

Electrolytes

Soluble in H2O

Insoluble in non-aqueous solvents

Solid at room conditions

Giant covalent bond

High b.p.& m.p.

Lots of energy required to break covalent bonds

Hard

X conduct electricity

X mobile ions

Insoluble in both H2O& non-aqueous solvents

X compensated by interaction

Eg. diamond, quartz

New node

Allotropes of carbon

Diamond

Graphite

Layer Structure

Conduct electricity

Structure with network of hexagons

1 e- left

Slippery

Weak intermolecular force

Giant metallic bond

Giant lattice of atoms

e- move freely throughout lattice

Solids with high m.p& b.p.

High density

Packed closely

Malleable& ductile

Metal atoms slide across each other

Can conduct electricity

Present of mobile e-

Conduct heat

Movement of mobile e-

Molecular Structure

Simple Molecular Solids

Discrete Molecules

Within molecules: strong covalent bond

Between molecules: weak van deer Waals' forces

Low b.p& m.p.

Little energy used to break intermolecular forces

Strong covalent bonds preserved

Soft

Easy to break van deer Waals' forces

Insoluble in H2O

Soluble in non-aqueous solvents

X conduct electricity

X mobile ion

Gas, volatile liquid, solid with low b.p.

Eg. CO2

Macromolecules

Contain hundreds& thousands of atoms