C3

Question 1

What’s a metallic bond?

Answer 1

The electrostatic attraction between positively charged metal ions which share a sea of delocalised electrons

Question 1

What’s an ionic bond?

Answer 1

The electrostatic attraction between two oppositely charged ions

Question 2

What’s a covalent bond?

Answer 2

A strong bond between atoms that share a pair of electrons

Question 3

What’s the difference between evaporation and boiling?

Answer 3

Evaporation - happens at any temp, at the surface
Boiling - happens at boiling point, throughout the liquid

Question 4

When metal atoms react with non-metal atoms, electrons…

Answer 4

are transferred to form ions

Question 5

Describe ionic compounds

Answer 5

• regular structures (lattice)
• strong electrostatic forces of attraction in all directions between oppositely charged ions

Question 6

Why do giant ionic compounds have a high melting and boiling point?

Answer 6

Strong electrostatic forces between oppositely charged ions take a lot of energy to break

Question 7

Why can giant ionic compounds only conduct electricity when molten or in a solution?

Answer 7

When solid, ions are fixed so cannot move to carry a charge, but when molten or in a solution, they are free to move and carry a charge

Question 8

Why do metals have high melting points?

Answer 8

It takes a lot of energy to break strong metallic bonds

Question 9

Why can metals conduct heat and electricity?

Answer 9

Electrons are delocalised so are free to move and carry heat or charge

Question 10

Why are metals malleable and ductile?

Answer 10

Atoms are in layers that can slide over each other

Question 11

Why are alloys made?

Answer 11

Pure metals are too soft for many uses so are mixed with other metals to make alloys which are harder

Question 12

what happens when non-metal atoms react with other non-metal atoms?

Answer 12

Electrons are shared to form a covalent bond

Question 13

What are simple covalent molecules usually?

Answer 13

gases or liquids that have low melting and boiling points

Question 14

Simple covalent bonds have _____ bonds between atoms but _______

Answer 14

• strong covalent
• weak intermolecular

Question 15

Why do simple covalent molecules have low melting and boiling points?

Answer 15

weak intermolecular forces mean not much energy is needed to break them

Question 16

Intermolecular forces ____ with size, so ____- molecules have ___ melting and boiling points

Answer 16

• increase
• larger
• higher

Question 17

What’s a limitation of a 2D model?

Answer 17

Doesn’t show the shape of the molecule

Question 18

What’s a limitation of a ball and stick model?

Answer 18

Doesn’t show electrons in bonds

Question 19

What’s a limitation of a giant structure?

Answer 19

Doesn’t show true number of atoms

Question 20

what is a giant covalent structure?

Answer 20

Solids with very high melting points, with atoms joined by strong covalent bonds

Question 21

Describe graphite (5)

Answer 21

• carbon atoms in hexagonal rings
• each carbon atom has 3 strong covalent bonds and 1 delocalised electron
• high melting point
• can conduct electricity
• soft because weak forces let layers slide over each other

Question 22

Describe diamond (5)

Answer 22

• made of carbon atoms
• 4 strong covalent bonds
• high melting point
• can’t conduct electricity
• very hard - each atom held in place by 4 strong covalent bonds

Question 23

as the side of a cube decreases by a factor of 10, the surface area to volume ratio…

Answer 23

increases by a factor of 10

Question 24

Nanoparticles have different properties to same materials in bulk, because of…

Answer 24

their high surface area to volume ratio

Question 25

describe graphene (4)

Answer 25

• layer of graphite
• can conduct electricity
• used for electronics and composites
• VERY hard

Question 26

describe fullerene (4)

Answer 26

• a hollow shape made from graphene
• Buckminster fullerene C60 has a spherical shape
• Carbon nanotubes are cylindrical shapes
• Good for nanotechnology, electronics and materials

Question 27

Why are fullerenes good for nanotechnology?

Answer 27

Conduct heat and electricity

Question 28

what do dot and cross diagrams show?

Answer 28

• charge of ions
• arrangement of electrons in an atom or ion
• which element the ion has come from (i.e magnesium)

Question 29

what dont dot and cross diagrams show?

Answer 29

• the structure of the compound
• the size of the ions