C3 Bonding

Question 1

How are covalent bonds formed?

Answer 1

by atoms sharing electrons

Question 2

Which type of atoms form covalent bonds between them?

Answer 2

non-metals

Question 3

Describe the structure and bonding of a giant covalent substance.

Answer 3

billions of atoms bonded together by strong covalent bonds

Question 4

Describe the structure and bonding of small molecules.

Answer 4

small numbers of atoms group together into molecules with strong covalent bonds between the atoms and weak intermolecular forces between the molecules

Question 5

Describe the structure and bonding of polymers.

Answer 5

many identical molecules joined together by strong covalent bonds in a long chain, with weak intermolecular forces between the chains

Question 6

Why do giant covalent substances have high melting points?

Answer 6

it takes a lot of energy to break the strong covalent bonds between the atoms

Question 7

Why do small molecules have low melting points?

Answer 7

only a small amount of energy is needed to break the weak intermolecular forces

Question 8

Why do large molecules have higher melting and boiling points than small molecules?

Answer 8

the intermolecular forces are stronger in large molecules

Question 9

Why do most covalent substances not conduct electricity?

Answer 9

do not have delocalised electrons or ions

Question 10

Describe the structure and bonding in graphite.

Answer 10

each carbon atom is bonded to three others in hexagonal rings arranged in layers - it has delocalised electrons and weak forces between the layers

Question 11

Why can graphite conduct electricity?

Answer 11

the delocalised electrons can move through the graphite

Question 12

Explain why graphite is soft.

Answer 12

layers are not bonded so can slide over each other

Question 13

What is graphene?

Answer 13

one layer of graphite

Question 14

Give two properties of graphene.

Answer 14

strong, conducts electricity

Question 15

What is a fullerene?

Answer 15

hollow cage of carbon atoms arranged as a sphere or a tube

Question 16

What is a nanotube?

Answer 16

hollow cylinder of carbon atoms

Question 17

Give two properties of nanotubes.

Answer 17

high tensile strength, conduct electricity

Question 18

Give three uses of fullerenes.

Answer 18

lubricants, drug delivery (spheres), high-tech electronics

Question 19

What is an ion?

Answer 19

atom that has lost or gained electrons

Question 20

Which kinds of elements form ionic bonds?

Answer 20

Metals and non-metals

Question 21

What charges do ions from Groups 1 and 2 form?

Answer 21

Group 1 forms 1+, Group 2 forms 2+

Question 22

What charges do ions from Groups 6 and 7 form?

Answer 22

Group 6 forms 2-, Group 7 forms 1-

Question 23

Name the force that holds oppositely charged ions together.

Answer 23

electrostatic force of attraction

Question 24

Describe the structure of a giant ionic lattice.

Answer 24

regular structure of alternating positive and negative ions, held together by the electrostatic force of attraction

Question 25

Why do ionic substances have high melting points?

Answer 25

electrostatic force of attraction between positive and negative ions is strong and requires lots of energy to break.

Question 26

Why don't ionic substances conduct electricity when solid?

Answer 26

ions are fixed in position so cannot move, and there are no delocalised electrons

Question 27

When can ionic substances conduct electricity?

Answer 27

when melted or dissolved

Question 28

Why do ionic substances conduct electricity when melted or dissolved?

Answer 28

ions are free to move and carry charge

Question 29

Describe the structure of a pure metal.

Answer 29

layers of positive metal ions surrounded by delocalised electrons

Question 30

Describe the bonding in a pure metal.

Answer 30

strong electrostatic forces of attraction between metal ions and delocalised electrons

Question 31

What are four properties of pure metals?

Answer 31

malleable, high melting/boiling points, good conductors of electricity, good conductors of thermal energy

Question 32

Explain why pure metals are malleable.

Answer 32

layers can slide over each other easily

Question 33

Explain why metals have high melting and boiling points.

Answer 33

electrostatic force of attraction between positive metal ions and delocalised electrons is strong and requires a lot of energy to break

Question 34

Why are metals good conductors of electricity and of thermal energy?

Answer 34

delocalised electrons are free to move through the metal

Question 35

What is an alloy?

Answer 35

mixture of a metal with atoms of another element

Question 36

Explain why alloys are harder than pure metals.

Answer 36

different sized atoms disturb the layers, preventing them from sliding over each other

Question 37

How big are nanoparticles?

Answer 37

1-100 nm

Question 38

How are nanomaterials different from bulk materials?

Answer 38

nanomaterials have a much higher surface area-to-volume ratio

Question 39

What is the relationship between side length and surface area-to-volume ratio?

Answer 39

as side length decreases by a factor of ten, the surface-area-to-volume ratio increases by a factor of ten

Question 40

What are nanoparticles used for?

Answer 40

used in healthcare, electronics, cosmetics, and catalysts