Bonding, Structure and Properties of Matter

Question 1

What are the three forms of chemical bonding?

Answer 1

• Ionic
• Covalent
• Metallic

Question 2

Which elements form an ionic bond?

Answer 2

Metals and non-metals

Question 3

Describe ionic bonding.

Answer 3

An element will lose or gain electrons to have a full outer shell- the element is now charged and thus ionised. An ionic crystal lattice is formed between the elements; held by electrostatic attraction between oppositely charged ions.

Question 4

What can ionic bonding form?

Answer 4

Giant ionic structures

Question 5

Why do giant ionic structures form?

Answer 5

The strong electrostatic attraction produced from oppositely charged ions acts in all directions clumping ions together. Examples, Sodium chloride.

Question 6

Which elements form a covalent bond?

Answer 6

Non-metals

Question 7

Describe covalent bonding.

Answer 7

Electrons will be shared between elements to have full outer shells. This can be both large (e.g. Polymers) or (e.g. Monomers) small.

Question 8

Name some giant covalent structures.

Answer 8

Diamond (carbon) and silicon dioxide

Question 9

Which elements form a metallic bond?

Answer 9

Metals

Question 10

Describe metallic bonding.

Answer 10

Electrons in a metals outer shell become delocalised and move through the whole structure. This gives rise to a strong bond. Atoms are arranged in a regular fashion.

Question 11

What is the standard model for the states of matter?

Answer 11

That there are:

• Solids
• Liquids
• Gases

Question 12

What are the limitations of the standard model for the states of matter?

Answer 12

The model assumes no forces are involved, all particles are represented as spheres and that they are solid/

Question 13

What dictates the energy required to change the state of a substance?

Answer 13

The structure and the strength of the forces between the ions/ atoms. The stronger the forces the higher the energy needed to change state.

Question 14

What are (and list) the state symbols?

Answer 14

The symbols given to define the state of a substance in a reaction;
Solid (s), Gas (g), Liquid (l) and an Aqueous solution (aq)

Question 15

List the properties of ionic compounds:

Answer 15

• Strong electrostatic forces in a giant ionic lattice
• Strong intermolecular bonds (oppositely charged ions)
• High melting/ boiling point
• Conductive in an aqueous or liquid state as ions become able to freely move

Question 16

List the properties of small compounds:

Answer 16

• Low melting/ boiling point
• Usually a liquid or gas at room temperature
• Weak intermolecular forces (stronger with size)
• Are not conductive

Question 17

List the properties of polymers:

Answer 17

• Very long molecules
• Strong covalent (molecular) bonds
• Strong intermolecular bonds
• Solid at room temperature
• High melting/ boiling point

Question 18

List the properties of giant covalent structures:

Answer 18

• All atoms in the substance are bonded together and so must be overcome to change state
• High melting/ boiling point
• Examples; Diamond, Graphite, SIlica

Question 19

List the properties of metals:

Answer 19

• Giant structures with strong molecular bonds
• High melting/ boiling point
• Regular structure to atoms
• Layers slide past; pliable, can be bent or shaped
• Conductive

Question 20

Why do we form alloys?

Answer 20

The mixture forms irregularities in the alloys structure. Thus, layers cannot slide past each other as easily and the material is harder.

Question 21

What are the three/ four main possible pure forms of carbon?

Answer 21

Diamond, Graphite, Graphene, Fullerens

Question 22

Describe diamond:

Answer 22

Each carbon atom bonds to four others in a giant covalent structure. Very hard but not conductive.

Question 23

Describe graphite/ graphene:

Answer 23

Each carbon bonds to three others in layers. The structure is hexagonal with no links between layers. One electron from each atom is delocalised and it is thus conductive.
Graphene is a single graphite layer.

Question 24

Describe fullerenes:

Answer 24

Carbon atoms bond in rings of several atoms in spheres or cylindrical tubes. The first discovered was the sphere Buckminsterfullerene. They are useful because; they are conductive (delocalised electrons), high length to diameter ratios. Can be used in nanotechnology, electronics and in new materials.

Question 25

What are the scales of matter?

Answer 25

Coarse particles (PM₁₀) or dust, Fine particles (PM₂.₅) 100- 2500 nm, Nanoparticles 1-100 nm.

Question 26

How do surface area and volume increase?

Answer 26

Both interact linearly in opposition to one another/ inverse.

Question 27

Why are nanoparticles useful?

Answer 27

High surface area to volume ratio induces interesting properties.

Question 28

How can nanoparticles be used?

Answer 28

Medicine, Electronics, Medicine, Cosmetics, Sun-cream, Deodorants, Catalysts.

Question 29

What are possible harmful effects of nanoparticles?

Answer 29

Potentially toxic, could enter the brain through the blood. Additional research needs to be done before wider spread use.