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Basics:

Dipole-Dipole forces(permanently polar molecules) + and parts of the molecules attract electrostatically giving Bts higher thanthose of non polar molecules of similar size.

Dispersion/Van der waals forces(non polar molecules)Temporary dipoles form between molecules because of mobile electron

density within the molecule. + on one molecule will induce a on a nearby one and so on, tho theres a net attraction betweenmolecules

Higher forces: More electrons Larger area of contact(larger molecules/atoms) Linear instead of branched chains

There will be bigger van der waals forces as Atomic/molecular size increases More shells of electrons

For large molecules dispersion forces can exceed dipole-dipole attraction

Molecular covalent substances Bonded strongly within themolecule but weakly between molecules

Properties depend on intermolecular forces

Intramolecular bonds Covalent Ionic

Metallic

Intermolecular bonds Van der Waals forces

Dipole dipole attraction

Hydrogen bonds strongest

Ionic bond The electrostatic attraction between + andions

formed by complete transfer of electron/s

Covalent bond Sharing a pair of electrons, one pair to a bond

(rather than complete transfer)

Polarisability The ease with which the electron cloud of an

anion is distorted by a cation so theres electron sharing

Hydrogen bond Electrostatic attraction between a strongly + H atom attached covalently to a highly electronegative element

F/N/O and a strongly F/N/O atom on another molecule, H bonds are longer than covalent bonds- Compounds which can H bond with water are very soluble (glucose, has OH groups that H bond with water)

Strong acidsHCl + water H+ + ClIonise(dissociate)almost completely, nearly every H atom released to become a hydrated proton, lots of H

+(aq) ions

Weak acids H2CO3 + water H

+

+ HCO3

weak acid equilibrium lies to the left so most of the acid wont be ionisedIonise(dissociate)slightly, little H atoms released, little H+(aq)ions

Strong acids and concentrated acids OR weak acids and dilute acids arent the same

Strong weak refers to how much the acid has ionised Concentrated dilute refers to molcm3of the acid

Acids proton donors

Acids mixed with water release H+

which combine with H2O(hydrated)to form hydroxonium ions H3O+

HCl(g) + H2O(l) H+(aq) + Cl

(aq) HCl(g) doesnt release hydrogenions until it meets water so HCl(g) isnt an acid

Bases proton acceptors, make OHhydroxyl ions when dissolved in water

Salt A compound formed by replacing hydrogen in an acid by a metal

The Periodic Table II (Period 3) Variation of properties across a period

Know Period 3 elements reactions with oxygen, chlorine and water

Na Mg Al Si P S Cl Ar

H2OHydrolysis

NaOH+ H2

MgO+ H2

- - - - HCl +HOCl

-

O2 Na2O2 MgO Al2O3 SiO2 P4O10 SO2 - -

Cl2 NaCl MgCl2 Al2Cl6 SiCl4 PCl5 S2Cl2 - -

Know the formulae and acid-base character of Na2O, NaOH, MgO, Mg(OH)2, Al2O3, Al(OH)3, SiO2, P4O10, SO2, SO3, Cl2O

and structure/bonding of the oxides

Know the reactions with water of NaCl, MgCl2, AlCl3, SiCl4, PCl3, PCl5, S2Cl2 and structure/bonding of the chlorides

Na2O MgO Al2O3 SiO2 P4O10 SO2 Cl2O

Ionic lattice Ionic covalent

lattice

Giant

covalent

Molecular covalent

NaCl MgCl2 Al2Cl6 SiCl4 PCl3 PCl5 S2Cl2

Giant ionic lattice solidsStrongionic attractions Molecular covalent - weaker intermolecular forces (van der Waals dispersionforces)

Basic Amphoteric Can actboth as acid & base

Acidic

NaCl MgCl2 Al2Cl6 SiCl4 PCl3 PCl5 S2Cl2

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H2O Na+(aq) +

Cl-(aq)

Mg2+(aq)

+

2Cl-(aq)

See below SiO2(s) +

HCl(aq)

H3PO3(aq) +

HCl(aq)

H3PO4(aq) +

HCl(aq)

-

Neutral solutions non

vigorous reaction

Covalent chlorides have polar bonds which undergo nucleophilic attack by the lone pair

on the H2O molecule. Reactions violent, fume in moist air(HCl(g))

Na2O MgO Al2O3 SiO2 P4O10 SO2 SO3 Cl2O

H2O NaOH Mg(OH)2 - - H3PO4 H2SO3 H2SO4 HOCl

Na2O

NaOH

MgO

Mg(OH)2

Al2O3Al(OH)3

SiO2 P4O10 SO2 SO3 Cl2O

HCl NaCl

+H2O

MgCl2

+H2O

AlCl3

+H2O

- - - - -

H2SO4 Na2SO4+H2O

MgSO4+H2O

Al2(SO4)3+H2O

NaOH - - a3Al(OH)6 Na2SiO3+H2O

NaH2PO4+H2O

Na2SO3+H2O

Na2SO4+H2O

NaOCl

+H2O

Al2O3+ 6NaOH + 3H2O --> 2Na3Al(OH)6

2 ionic equations showing amphoteric behaviour of aluminium oxide

Al2O3 (s) + 6H+(aq) 2Al3+ (aq) + 3H2O (l)

A12O3 + 6OH + 3H2O 2AI(OH)63

Questions:

What type of bonding would you expect in aluminium fluoride and why?

Ionic Fl ion is very small and has only 1- charge which makes it hard to become polarised

State the type of bonding in sodium oxide and explain how particles react to form the product in Na2O + H2O

2NaOH

Ionic O2 ion very polarisable/strong interaction with polar water reacting with water to give OH

What types of bonding exist in aluminium chloride, Al2Cl6? Dative covalent

NaCl(s) + H2O(l) Na+(aq) + Cl(aq) PCl3 + 3H2O H3PO3 3HClAccount for the difference in the changes by comparing the bonding in these two chlorides.

NaCl is ionic so dissolves in water/ions separate PCl3 is covalent so hydrolyses in water

Relate the acid-base character of the oxides sodium and phosphorus to the variation in metallic character of theelements in Period 3 of the Periodic Table (sodium to argon).

The Periodic Table II (Group 4) Variation of properties down a group

Recall the reasons for increase in metallic character down Group 4

Remember: Metallic character increases- atomic radius increases- ionisation energies fall- ions less polarising

Understand:

- As atoms become larger, they more easily lose electrons to form cations- Increase in metallic bonding, electrostatic attraction between lattice of cations and sea of delocalised electrons

- Increase in strength, malleable, ductile, good conductor of heat & electricity- More able to form ionic bonds with non metals

Recall physical properties of the elementsPhysical propertiesProperties that do not change the chemical nature of matter. Eg color, smell, boiling point

Group 4As atomic number increases, Bt decreases, density increases

AlCl3(s)+ 6H2O(l) [Al(H2O)6]3+

(aq) + 3Cl-(aq)

[Al(H2O)6]3+(aq) [Al(OH)(H2O)5]

2+(aq) + H+(aq)

AlCl3(s)+ H2O(l) AlCl2OH(aq) + HCl(aq)

AlCl2OH(aq) + H2O(l) AlCl(OH)2(aq) + HCl(aq)

AlCl(OH)2(aq)+ H2O(l) Al(OH)3(s) + HCl(aq)

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Carbon (C) Non-metal Solid (graphite) shiny

black

(diamond)

colourless

Conducts along

layers

Non-conductor

Giant covalent layer

lattice

Giant covalent

Silicon (Si) Metalloid Solid dark grey-blue Semi conductor Giant covalent

Germanium(Ge)

Metalloid Solid Grayish white Semi conductor Giant covalent

Tin (Sn) Metal Solid Yellowy-silver Conductor Metallic

Lead (Pb) Metal Solid Grey-silver Conductor Metallic

The oxides acid-base characteristics & equations

CO

CO2

Neutral

Weakly Acidic

Does not react with water. CO + NaOH HCOONaCO2 + H2O --> H2CO3

SiO2 Acidic SiO2 + 2NaOH --> 2Na2SiO3 + H2O

GeO GeO2

SnO SnO2

PbO PbO2

Amphoteric As an acid: XO + NaOH + H2O --> Na2X(OH)4SnO2 + 2NaOH H2O + Na2SnO3

As a base: XO + HCl --> XCl2 + H2O

XO2 + HCl --> XCl4 + H2O

PbCl4 decomposes showing the oxidising nature of lead(IV)oxide

PbCl4 PbCl2 + Cl2

Questions:

Give an equation to show why solutions of carbon dioxide in water are acidic

CO2+H2OH+ + HCO3

-

State how the metallic character of the Group 4 elements changes with an increase in atomic number

Increases as atoms become larger (so) more easily lose electrons

As atomic number increases in group 4 the metallic character of the elements increases. Explain how this increase in metallic

character is demonstrated in the acid-base properties of carbon dioxide and of lead(II) oxide

Metal oxides are (more) basic than non-metal oxides CO2 acidic PbO amphoteric

Recall that +2 oxidaton state in Group 4 becomes more stable than the +4 oxidation state down the group and apply this to the

chemistry of tin and lead

Redox (reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number/state changedOxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic

Oxidation describes the loss ofelectrons by a molecule, atom or ion (From +2 to +4)

Reduction describes the gain ofelectrons by a molecule, atom or ion (From +4 to +2)

heatSnO2(s) No reaction

More stable

SnO2doesnt decompose,tin more stable in the +4 ox state

Lead(+2) shows no reducing propertiesLead(IV) oxide oxidises chloride to chlorine

lead(II)chloride

PbO2(s) + 4HCl(aq) PbCl2(s) + Cl(g) + 2H2O(l)

(+4) (+2)reducedheat

PbO2(s) PbO(s) +

O2(g)

More stable

PbO2 decomposes to PbO + O2lead more stable in +2 ox state

Questions:

I SnO2+ 4HClSnCl2+ Cl2+ 2H2O II SnO2+ 4HClSnCl4+ 2H2O

Which of the above reactions is more likely. Explain your reasoning.

Tin is more stable in +4 than +2 oxidation state therefore Sn(IV) not reduced (by Cl-/HCl)

Reasons for the difference in behaviour of SnO2 and PbO2 with concentrated hydrochloric acid

In tin oxidation state +4 more stable than +2

In lead oxidation state +2 is more stable than +4

Therefore lead(IV) oxidises chloride ion (to chlorine)

Recall and explain the structure of carbon tetrachloride

Tetrahedral configuration joined to a carbon atom, in the center, by single covalent bonds. Because of this

symmetrical geometry, the molecule has no net dipole moment; that is, CCl4 is non-polar.

http://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Moleculehttp://en.wikipedia.org/wiki/Atomhttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Moleculehttp://en.wikipedia.org/wiki/Atomhttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Tetrahedronhttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Covalent_bondhttp://en.wikipedia.org/wiki/Dipole_momenthttp://en.wikipedia.org/wiki/Image:Carbon_Tetrachloride.svghttp://en.wikipedia.org/wiki/Dipole_momenthttp://en.wikipedia.org/wiki/Covalent_bondhttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Tetrahedronhttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Atomhttp://en.wikipedia.org/wiki/Moleculehttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Atomhttp://en.wikipedia.org/wiki/Moleculehttp://en.wikipedia.org/wiki/Electron

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Recall and explain the behaviour of carbon tetrachloride with water and contrast this behaviour with that of silicon tetrachloride

with water

Chloride(Tetrahalides) Nature

CCl4(tetrachloromethane) Molecular covalent liquid, doesnt hydrolyse CCl4 + 2H2OCO2 + 4HCl

lone pair on oxygen in water cannot attack C atom

because C atom too small / Cl atom too large

SiCl4(silicon

tetrachloride)

SiCl4+ 2H2O SiO2+ 4HCl Carried out in fume cupboard, as HCl is irritant/harmfulMolecular covalent liquid, hydrolyses

due to electron pair donation by water to empty d orbitals of Si atom

Rapid hydrolysis due to electron pair donation by water to empty d orbitals of Si atom In this hydrolysis Si-Cl bonds dont have to be broken before Si-O bonds form

EACT for this hydrolysis therefore much lower than CCl4

Less steric effects in larger molecule

Questions:

Carbon tetrachloride and silicon tetrachloride behave in different ways when added to water. State how each chloride behaves andexplain the difference

SiCl4 reacts/hydrolyses, CCl4 does not

(lone) pair of electrons (from the oxygen atom) in a water molecule

Cannot form a bond with/be donated to the C atom

C is a small atom surrounded by large Cl atoms (so attack is sterically hindered)