Topic 1

Question 1

Properties of ionic compound

Answer 1

Ionic​ ​compounds​ ​are​ ​made​ ​up​ ​of​ ​a​ ​metal​ ​and​ ​a​ ​nonmetal
● Ionic​ ​compounds​ ​have​ ​regular​ ​structures​ ​(giant​ ​ionic​ ​lattices)​ ​in​ ​which​ ​there​ ​are
strong​ ​electrostatic​ ​forces​ ​of​ ​attraction​ ​in​ ​all​ ​directions​ ​between​ ​oppositely
charged​ ​ions.
● They​ ​have​ ​​high​ ​melting​ ​and​ ​boiling​ ​points​,​ ​because​ ​a​ ​lot​ ​of​ ​energy​ ​is​ ​required​ ​to
break​ ​the​ ​many​ ​strong​ ​bonds.
● When​ ​melted​ ​or​ ​dissolved​ ​in​ ​water,​ ​ionic​ ​compounds​ ​​conduct​ ​electricity​​ ​because
the​ ​ions​ ​are​ ​free​ ​to​ ​move​ ​and​ ​carry​ ​current,​ ​and​ ​they​ ​​do​ ​not​ ​conduct​ ​electricity as​ ​solids,​​ ​because​ ​the​ ​ions​ ​are​ ​fixed​ ​and​ ​are​ ​not​ ​able​ ​to​ ​move,​ ​carrying​ ​charge with​ ​them.
● Often​ ​dissolve​ ​in​ ​water​​ ​to​ ​form​ ​an​ ​aqueous​ ​solution

Question 2

Properties of simple molecular compounds

Answer 2

Substances​ ​that​ ​consist​ ​of​ ​small​ ​molecules​ ​are​ ​usually​ ​gases​ ​or​ ​liquids​ ​that​ ​have
low​ ​boiling​ ​and​ ​melting​ ​points​.​ ​They​ ​are​ ​made​ ​up​ ​of​ ​nonmetal​ ​elements.
● Substances​ ​that​ ​consist​ ​of​ ​small​ ​molecules​ ​have​ ​weak​ ​intermolecular​ ​forces
between​ ​the​ ​molecules.​ ​These​ ​are​ ​broken​ ​in​ ​boiling​ ​or​ ​melting,​ ​​not​ ​the​ ​covalent bonds.​
○ The​ ​intermolecular​ ​forces​ ​increase​ ​with​ ​the​ ​size​ ​of​ ​the​ ​molecules,​ ​so larger​ ​molecules​ ​have​ ​higher​ ​melting​ ​and​ ​boiling​ ​points.
● Substances​ ​that​ ​consist​ ​of​ ​small​ ​molecules​ ​​don’t​ ​conduct​ ​electricity​,​ ​because small​ ​molecules​ ​do​ ​not​ ​have​ ​an​ ​overall​ ​electric​ ​charge.​ ​although,​ ​some breakdown​ ​in​ ​water​ ​to​ ​form​ ​ions​ ​which​ ​can​ ​conduct​ ​electricity
● Many​ ​are​ ​insoluble​ ​in​ ​water,​ ​but​ ​some​ ​are​ ​soluble​​ ​because​ ​they​ ​can​ ​form intermolecular​ ​forces​ ​with​ ​water​ ​which​ ​are​ ​stronger​ ​than​ ​those​ ​between​ ​water molecules​ ​or​ ​their​ ​own​ ​molecules​ ​already​ ​(e.g.​ ​CO​2​​ ​and​ ​NH​3​​ ​are​ ​soluble)

Question 3

Giant covalent structures

Answer 3

They​ ​are​ ​made​ ​up​ ​of​ ​nonmetal​ ​elements
● Substances​ ​that​ ​consist​ ​of​ ​giant​ ​covalent​ ​structures​ ​are​ ​solids​ ​with​ ​​very​ ​high
melting​ ​points​.
o All​ ​of​ ​the​ ​atoms​ ​in​ ​these​ ​structures​ ​are​ ​linked​ ​to​ ​other​ ​atoms​ ​by​ ​strong
covalent​ ​bonds.
▪ These​ ​bonds​ ​must​ ​be​ ​overcome​ ​to​ ​melt​ ​or​ ​boil​ ​these​ ​substances.
● some​ ​giant​ ​covalent​ ​structures​ ​can​ ​conduct​ ​electricity​,​ ​whereas​ ​others​ ​can’t

Question 4

Properties of metals

Answer 4

Metals​ ​consist​ ​of​ ​giant​ ​structures​ ​of​ ​atoms​ ​arranged​ ​in​ ​a​ ​regular​ ​pattern.​ ​They
are​ ​always​ ​made​ ​up​ ​of​ ​just​ ​metallic​ ​elements
● The​ ​electrons​ ​in​ ​the​ ​outer​ ​shell​ ​of​ ​metal​ ​atoms​ ​are​ ​delocalised​ ​and​ ​so​ ​are​ ​free​ ​to
move​ ​through​ ​the​ ​whole​ ​structure.
● The​ ​sharing​ ​of​ ​delocalised​ ​electrons​ ​gives​ ​rise​ ​to​ ​strong​ ​metallic​ ​bonds.

Question 5

Properties of metals part 2

Answer 5

Metals​ ​have​ ​giant​ ​structures​ ​of​ ​atoms​ ​with​ ​strong​ ​metallic​ ​bonding.
o o
o o o
​​ ​​
Therefore,​ ​most​ ​metals​ ​have​ ​​high​ ​melting​ ​and​ ​boiling​ ​points​.
They​ ​can​​ ​conduct​ ​heat​ ​and​ ​electricity​​ ​because​ ​of​ ​the​ ​delocalised electrons​ ​in​ ​their​ ​structures.
Conduction​ ​depends​ ​on​ ​the​ ​ability​ ​for​ ​electrons​ ​to​ ​move​ ​throughout​ ​the metal.
The​ ​layers​ ​of​ ​atoms​ ​in​ ​metals​ ​are​ ​able​ ​to​ ​slide​ ​over​ ​each​ ​other,​ ​so​ ​metals can​ ​be​ ​bent​ ​and​ ​shaped.
insoluble​ ​in​ ​water​-​ ​but​ ​some​ ​will​ ​react​ ​with​ ​it​ ​instead

Question 6

1.33 Explain the properties of ionic compounds limited to: high melting
points and boiling points

Answer 6

High melting and boiling points - strong electrostatic forces
Conduct electricty molten - ions can move
Cant conduct - ions are fixed in place

Question 7

1.34 Explain the properties of typical covalent, simple molecular compounds
limited to: low melting points and boiling points, in terms of forces between
molecules (intermolecular forces) and poor conduction of electricity

Answer 7

Low melting point and boiling points - only weak forces betweeem molecules must be overcome, not covalent bonds
Poor conduction - no charged particles or electrons that are free to move

Question 8

Structure of diamond

Answer 8

In​ ​diamond​ ,​ ​each​ ​carbon​ ​is​ ​joined​ ​to​ ​4​ ​other​ ​carbons
covalently.
o It’s​ ​very​ ​hard,​ ​has​ ​a​​ ​very​ ​high​ ​melting​ ​point​​ ​and​ ​​does​ ​not
conduct​ ​electricity.

Question 9

Structure of graphite

Answer 9

In​ ​graphite,​ ​each​ ​carbon​ ​is​ ​covalently​ ​bonded​ ​to​ ​3​ ​other​ ​carbons,​ ​forming​ ​layers
of​ ​hexagonal​ ​rings,​ ​which​ ​have​ ​no​ ​covalent​ ​bonds​ ​between​ ​the​ ​layers.
o The​ ​layers​ ​can​ ​slide​ ​over​ ​each​ ​other​ ​due​ ​to​ ​no​ ​covalent​ ​bonds​ ​between
the​ ​layers,​ ​but​ ​weak​ ​intermolecular​ ​forces.​ ​Meaning​ ​that​ ​graphite​ ​is​ ​​soft
and​ ​slippery.

This​ ​makes​ ​graphite​ ​similar​ ​to​ ​metals,​ ​because​ ​of​ ​its​ ​delocalised electrons.
It​​ ​can​ ​conduct​ ​electricity​ ​​–​ ​unlike​ ​diamond.

Question 10

Graphite uses

Answer 10

Electrodes​ ​–​ ​graphite​ ​can​ ​conduct​ ​electricity​ ​–​ ​unlike​ ​Diamond
o Lubricant​ ​–​ ​weak​ ​intermolecular​ ​forces​ ​and​ ​no​ ​covalent​ ​bonds​ ​between
the​ ​layers,​ ​therefore​ ​it​ ​is​ ​soft​ ​and​ ​slippery

Question 11

Diamond uses

Answer 11

Cutting tools - very gard, due to its rigid structure

Question 12

1.38 Explain the properties of fullerenes including C60s and graphene in terms of their structures and bonding

Answer 12

Graphene
o Single​ ​layer​ ​of​ ​graphite
o Has​ ​properties​ ​that​ ​make​ ​it​ ​useful​ ​in​ ​electronics​ ​and​ ​composites

Question 13

Carbon can also from fullerene. How

Answer 13

Molecules​ ​of​ ​carbon​ ​atoms​ ​with​ ​hollow​ ​shapes
o They​ ​are​ ​based​ ​on​ ​hexagonal​ ​rings​ ​of​ ​carbon​ ​atoms,​ ​but​ ​they​ ​may​ ​also
contain​ ​rings​ ​with​ ​five​ ​or​ ​seven​ ​carbon​ ​atoms oThe​​first ​​fullerene​​ to ​​be ​​discovered​​ was​​Buckminsterfullerene ​​(C6​0)​,​​which
has​ ​a​ ​spherical​ ​shape

Question 14

Carbon nanotubes

Answer 14

Cylindrical​ ​fullerenes​ ​with​ ​very​ ​high​ ​length​ ​to​ ​diameter​ ​ratios
o Their​ ​properties​ ​make​ ​them​ ​useful​ ​for​ ​nanotechnology,​ ​electronics​ ​and
materials