Structure and bonding

Question 1

What are the three states of matter?

Answer 1

Solid, liquid and gas

Question 2

What is a compound?

Answer 2

A combination of two or more elements that are chemically bonded.

Question 3

What type of bonding does a compound that shares electrons between the compounds have? What type of elements are involved in this type of bonding?

Answer 3

Covalent bonding - can be double bonded or triple bonded.

ONLY between non-metals and particularly common in group 7 elements such as Chlorine.

Question 4

What type of bonding does a compound that transfers electrons have? What type of elements are involved in this type of bonding?

Answer 4

Ionic bonding - between the metal and non-metal.

A metal always loses electrons (therefore gaining charge) and a non-metal gains electrons (therefore losing charge.) E.g. Sodium chloride - Na + Cl -

Question 5

What is the arrangement called between the charged ions? hint - giant

Answer 5

Giant ionic lattice or Giant structure

Question 6

What are the characteristics of giant ionic structures?

Answer 6

High melting and boiling points - lots of energy required to break the electrostatic forces of attractions.
If molten or dissolved in water, they can conduct electricity because the charged particles can move around and carry electrical charge.

Question 7

What is a polymer?

Answer 7

A long chain of small unreactive molecules that bond to each other. The individual particles are called monomers.

Question 8

What is the force between molecules called?

Answer 8

Intermolecular force.

Question 9

What is a huge network of atoms that are covalently bonded called?

Answer 9

Giant covalent structure

Question 10

What is a metallic bond?

Answer 10

2 metals bonded together, with a sea of de-localised electrons in a positive charge. It is these de-localised electrons that can move around and carry charge, allowing metals to conduct electricity.

Question 11

Give 2 examples of giant covalent structures.

Answer 11

Diamond and graphite - both carbon

Question 12

What are characteristics of giant covalent bonds?

Answer 12

• High melting and boiling points
• insoluble in water
• Hard and do not conduct electricity (except for graphite)

Question 13

Why is graphite a good thermal and electrical conductor?

Answer 13

Has de-localised electrons that can move around and carry charge and heat energy.

This is because the carbon atoms are only bonded to three other carbon atoms, and as carbon has 4 electrons in its outer shell, it has a spare electron that is free to move around.

Question 14

Why is graphite slippery and soft?

Answer 14

There are weak intermolecular bonds between the different layers of graphite, so the layers can slide over each other.

Question 15

What is an allotrope?

Answer 15

The two or more physical forms that an element can exist in. For example, diamond and graphite are allotropes of carbon.

Question 16

Why are nano-particles able to react much more quickly than regular particles of the same element?

Answer 16

They have a high surface area-to-volume ratio and more particles can be in contact with the reactant.

Question 17

What is a nanometre?

Answer 17

A nanometre is 1 x 10^-9 metres, or 0.0000000001m (a billionth of a metre)

Question 18

What is nanoscience?

Answer 18

The science of particles between 1 and 100 nm small.

Question 19

What is a fullerene?

Answer 19

A hollow shaped-molecule of carbon

Question 20

Give two examples of fullerenes.

Answer 20

• Buckminsterfullerene: this fullerene is spherically shaped, meaning it can be useful as a lubricant as it can roll
• Carbon nanotube, which is a hollow tube of carbon

Question 21

What are some possible uses of fullerenes?

Answer 21

• Catalysts - they have a high surface area to volume ratio
• Reinforcing materials, due to their high tensile strength
• Electronics industry, due to their high electrical and thermal conductivity
• Delivering drugs into the body, due to their hollow shape that can carry drugs or radioactive atoms.

Question 22

What is graphene?

Answer 22

Graphene is a single layer of graphite, which is one atom thick. it has excellent electrical conductivity and has a very low density.

Question 23

Name some uses of nanoparticles?

Answer 23

Suncream can use nanoparticles as they are transparent and absorbed into the body.
Transporting drugs into the body e.g. for tumour cells
Reinforcing materials such as in tennis racquets.

Question 24

What are some possible risks of nanoparticles?

Answer 24

They are very reactive (due to high SA to V ratio) meaning that a small spark near the catalyst can cause a violent explosion
Breathing in nanoparticles can cause lung damage and they could enter the bloodstream due to their use in cosmetics
They could harm animals if they enter the environment