Chemistry - Bonding Structure
& Properties of matter
STRONG Chemical bonds
IONIC BONDING
Occurs in compounds
formed between METAL &
NON- METALS
Particles produced are
oppositely charged ions
Only electrons in outer shell
of METAL are TRANSFERRED
Metals - LOSE ELECTRONS - become
+ly charged ions/ non metals GAIN
ELECTRONS- become -ly charged ions
Ions produced by group 1+ 2
metals - and group 6+7 non
metals - has electronic
structure of NOBLE GAS ( group
0 - full outer shell)
METALLIC BONDING
Occurs in metallic
ELEMENTS & ALLOYS
Atoms have
DELOCALISED
electrons
FOUND ON THE OUTER SHELL- delocalised
electrons are free to move through WHOLE
STRUCTURE
Metals are giant atomic
structures arranged in a
REGULAR pattern
COVALENT BONDING
Atoms SHARE PAIRS of
electrons- covalent bonds are
STRONG
Occurs in NON metallic elements and
compounds of NON elements
Covalent bonded structures - either small
molecule, polymers ( large molecules) or giant
covalent structures ( i.e diamond/silicon
dioxide)
PROPERTIES OF SUBSTANCES
Limitations of particle
theory-/ simple model -
NO FORCES / all
particles are shown as
SOLID SPHERE
STATES SYMBOLS - (s) - solid / (l) liquid / (g) gas/ (aq)
aqueous solution - where the
solvent is water
PROPERTIES OF IONIC COMPOUNDS
Ionic compounds = regular structures/
lattices -have strong electrostatic forces
of attraction- in all directions = HIGH BPT
+ MPT- lots of energy needed to break
many strong bonds
Ionic compounds CAN CONDUCT ELECTRICITY
when melted or dissolved in water- IONS MOVE
& CHARGE CAN FLOW
PROPERTIES OF ALLOYS & METALS
Pure metals = are ARRANGED
IN LAYERS- so can be BENT/
SHAPED
But PURE METALS - too soft for
many uses - so are mixed with
OTHER metals - to make HARDER
ALLOYS
Alloys have a DISORDERLY
ARRANGEMENT due to
different size of atoms
METALS AS CONDUCTORS
Metals - good electrical conductors -
delocalised electrons can carry electric charge
through metal
Metals = good thermal conductors- energy
transferred via delocalised electrons
Most metals - have HIGH BPT +
MPT - due to srong metallic bonds
PROPERTIES OF GIANT COVALENT STRUCTURES
Giant covalent structures = SOLIDS w/ VERY HIGH MPT
Atoms are joined by strong covalent
bonds - that need to be overcome to
melt/boil substances- i.e carbon
allotropes ( silica/diamond)
PROPERTIES OF POLYMERS
Polymers - have v. LARGE molecules- the I.M.F(
INTERMOLECULAR FORCES) between polymers are
STRONG so substances are SOLID at room temp
Atoms in polymers - linked to other
atoms via STRONG COVALENT BONDS
PROPERTIES OF SMALL MOLECULES
Substamces made up of SMALL
molecules - usually
GASES/LIQUIDS- low MPT +BPT
Only have week I.M.F forces in between
molecules- these IMF and not covalent
bonds are broken when substance
melt/boils.
Note : IMF increases with
SIZE of molecules - larger
molecules = higher mpt + bpt
DON'T conduct ELECTRICITY -molecules don't have overall charge
Held together via Strong ELECTROSTATIC
FORCES OF ATTRACTION between
oppositely charged ions
Electrostatic forces - act is
ALL directions -forming a
LATTICE
EMPIRICAL FORMULA
EXAMPLE- Mg- 2e / Cl+2e -
gives the empirical formula
of MgCl2
CARBON STRUCTURES/ ALLOTROPES
DIAMOND - each carbon atoms
forms 4 COVALENT BONDS with
other carbon atoms - giant
covalent structure- Diamond is
VERY HARD/ HIGH MPT/
DOESN'T CONDUCT
ELECTRICITY
GRAPHITE - carbon atom form 3
COVALENT bonds w/ 3 other
carbon atoms- form
HEXAGONAL rings - NO
COVELENT BONDS BETWEEN
LAYERS
Graphite - has 1 DELOCALISED
ELECTRON from each carbon atom - so a
similar to metals in this way
GRAPHENE - single layer of
graphite- used in
electronics/composites
FULLERENES
Fullerenes are molecules of carbon atoms w/
HOLLOW SHAPES- are made from hexagonal rings of
carbona toms - may contain ring with 5 or 7 carbon
atoms too - i.e Buckminister Fullerene (C60)- it is a
sphere
CARBON NANOTUBES
ARE CYLINDRICAL fullerenes - have a HIGH length to
diameter ratio - properties make them USEFUL for
nanotechology/materials/electronics/cosmetics/catalysts
(NANO PARTICLES) Approx.1-100nm in diameter- so have
higher SA:VOL ratio - smaller quantities are needed for it
to be effective than normal size particles
LIMITATIONS OF DOT +
CROSS/ BALL AND STICK
DIAGRAMS
Ball + stick - pros - shows
charges on ions/ numer of atoms / 3D
arrangement/ cons - ions are
closer together/ false image of
bond direction
Melting & freezing happen at mpt /
boiling and condensing happen at
bpt
3 STATES OF MATTER
The energy required to change
states - depends on strength of
forces between particles and type
of bonding/strucutrw - stronger
bonging/forces = higher bpt &
mpt