THERE ARE 4 TYPES OF BONDS

-METALLIC

-IONIC

-COVALENT MOLECULAR

-COVALENT NETWORK

METALLIC BONDINGMETALLIC BONDING IS THE ATTRACTION BETWEEN POSITIVE METAL IONS AND THE SEA OF DELOCALISED ELECTRONS

Animation:

Delocalised electronsPositive metal ionshttp://www.drkstreet.com/resources/metallic-bonding-animation.swf

PROPERTIES OF METALS

PROPERTYEXPLANATIONHigh MP and BPStrong force of attraction between positive metal ions and delocalised electrons. Takes a lot of energy to separate, therefore high MP and BP.Hard and usually denseStrong force of attraction between metal ions and delocalised e- makes hard. Atoms tightly packed makes dense.Good conductor of heatAtoms tightly packed. Heat is passed on by direct contact easilyGood conductor of electricity (in all states)Delocalised electrons are able to carry the charge

Malleable (beaten into sheets) and ductile (drawn into wires)Bonding is non directional. Metallic bonding is able to be distorted without disrupting the metallic bonding

no change

IONIC BONDINGIONIC BONDING IS THE ATTRACTION BETWEEN OPPOSITELY CHARGED IONS arranged in a regular 3D lattice

PROPERTIES OF IONIC SUBSTANCES

PROPERTYEXPLANATIONHigh MP and BPStrong force of attraction between positive and negative ions means a lot of energy is needed to separate the ions, therefore high MP and BP.Hard and brittleHard as strong force of attraction exists between oppositely charged ions. Brittle (shatters when hit) as Positive and negative ions are arranged in a regular 3D lattice. Distortion causes repulsion between similarly charged ions.

apply a force causes repulsion between similarly charged ions

PROPERTIES OF IONIC SUBSTANCEScont.

PROPERTYEXPLANATIONNon conductor of electricity in solid stateIons are held in fixed positions. There are no mobile charged species free to carry the charge.

Good conductor of electricity in molten (melted) and aqueous (dissolved in water) statesIons are now free to move and carry the charge

COVALENT MOLECULARWeak FORCE OF ATTRACTION BETWEEN DISCRETE (individual) MOLECULESCONTAINS NON METALS ONLY

PROPERTIES OF COVALENT MOLEC

PROPERTYEXPLANATIONLow MP and BP (often gas at RT)Weak force of attraction is between molecules. Therefore not much energy is needed to separate them and hence low MP and BP

Soft solidsWeak force of attraction between molecules. Force or pressure can push the molecules to the sideNon conductor of electricity in ALL statesAll electrons are localised (in inner shells or covalent bond). There arent any electrons or other charged particles free to carry the charge.

COVALENT NETWORKStrong covalent bonding extends throughout the entire latticeC, Si, SiC and SiO2

PROPERTIES OF COVALENT NETWORK

PROPERTYEXPLANATIONVery high MP and BPStrong covalent bonding extends throughout entire lattice. Therefore A LOT of energy is needed to separate the atoms and hence high MP and BP.

Hard (except graphite which is slippery)Strong covalent bonding holds atoms in place making it hard (graphite is slippery due to its layers)

Non conductor of electricity in ALL states (except graphite)All electrons are localised in covalent bonds. There arent any electrons or other charged particles free to carry the charge. Graphite has layers and free e- to carry the charge in one planeinertE- are localised in covalent bonding and therefore unable to react

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