C2c -Properties of Metals

Question 1

1 why can carbon form so many different compounds

Answer 1

its in group 4, so has 4 outer shell electrons
can form four covalent bonds
join with other carbons to form chains and rings
form covalent bonds with other elements like hydrogen and oxygen

Question 2

1 what is the chemical symbol for carbon

Answer 2

C

Question 3

1 what is an allotrope

Answer 3

forms of an element in the same state but with different atomic arrangements with different properties

Question 4

1 what is diamond like

Answer 4

transparent but very hard (suitable for dental drills)
giant covalent structure where each atom is bonded to four others
very strong covalent bonds - lots of energy needed to break it
high melting point
all outer shell electrons are shared
no delocalised electrons, can’t conduct electricity
brittle and rigid- fracture easily
doesn’t dissolve in water

Question 5

1 what is graphite like

Answer 5

grey, black and soft
giant covalent structure
each atom has three bonds
one outer shell electron is not involved in bonding
becomes delocalised, free to move around structure
conducts electricity even though its a non-metal
layered structure - hexagons like chicken wire
strong covalent bonds give a high melting point
forces between layers are weak
slide over each other easily
slippery (pencil tip)

Question 6

1 what is graphene

Answer 6

a single layer of graphite
transparent, extremely strong, conducts electricity

Question 7

1 what are fullerenes

Answer 7

molecules shaped like tubes or balls

Question 8

1 what are nanotubes

Answer 8

resembles a sheet of graphene rolled into a tube
strong, lightweight
used to reinforce sports equipment
conduct electricity as only 3 carbons bonds
one electron is free to move

Question 9

1 what is a bucky ball
(Buckminster fullerenes)

Answer 9

60 carbon atoms
conduct electricity - only 3 carbon bonds- one is free to move
resembles a sheet of graphene closed to make a hollow ball
carbons atoms are pentagons and hexagons
uses as lubricants (act like ball bearings)
can pass through cell membranes due to small size
deliver medical drugs directly to cells

Question 10

2 what happens when substances change states

Answer 10

forces of attraction between particles are overcome
bonds break

Question 11

2 how many bonds break going from solid to liquid

Answer 11

some

Question 12

2 how many bonds break going from liquid to gas

Answer 12

all

Question 13

2 what are the different types of bond

Answer 13

metallic
ionic
covalent
intermolecular forces

Question 14

2 the stronger the bond….

Answer 14

the more energy needed to break them

Question 15

2 high melting points = …

Answer 15

if they have strong bonds in solid state

Question 16

2 high boiling points = …

Answer 16

strong bonds in liquid state

Question 17

2 when do bonds form

Answer 17

when a substance condenses or freezes
some form going from gas to liquid
all form going from liquid to solid
stored chemical energy is transferred to surroundings via heating

Question 18

2 what bonds are involved in metal?
what strength?
examples?

Answer 18

metallic bonds
strong
iron, mercury

Question 19

2 what bonds are involved in ionic compounds?
what strength?
examples?

Answer 19

ionic bonds
strong
sodium chloride

Question 20

2 what bonds are involved in giant covalent structures?
what strength?
examples?

Answer 20

covalent bonds
strong
diamond, silica

Question 21

2 what bonds are involved in simple molecules?
what strength?
examples?

Answer 21

intermolecular forces
weak
oxygen, water, wax

Question 22

2 what 3 substances are usually solid at room temp

Answer 22

metals
ionic compounds
giant covalent structures

Question 23

2 what state are simple molecular substances in at room temperature

Answer 23

liquid or gas
solid state but easily melted

Question 24

2 what is sublimation

Answer 24

change directly form solid to gas
below melting and boiling oints
exists as simple molecules attracted to each other by weak intermolecular forces
molecular pack together like a solid, but easily separated to form a vapour - gas
iodine

Question 25

3 what is brittle

Answer 25

breaks or cracks when an external force is applied

Question 26

3 what is malleable

Answer 26

change shape without cracking or breaking

Question 27

3 whats the difference between brittle and malleable in a substance

Answer 27

how easily the particles can change their position into the lattice structure

Question 28

3 why are metals malleable

Answer 28

even though bonds are strong
ions held in by a lattice by attractive forces to a sea of delocalised electrons
when a large enough force is applied, layers of metal slide over each other
because of the delocalised electrons being free to move, nothing breaks

Question 29

3 what happens with giant covalent structures
malleable or brittle?

Answer 29

held together by giant lattice by strong covalent bonds
if a big enough fore is applied, many covalent bonds and the substance break

Question 30

3 what happens with ionic compounds
malleable or brittle?

Answer 30

similar to covalent bonds
oppositely charge ions held together by a giant lattice by strong ionic bonds
usually brittle

Question 31

3 what happens with simple and polymer molecules

Answer 31

attracted to each other with weak intermolecular forces
easily broken

Question 32

3 what happens with simple and polymer molecules in a solid state

Answer 32

molecules arranged in a lattice
may be brittle
iodine crystals and some polymers are like this

Question 33

3 what happens with simple and polymer molecules not in a lattice

Answer 33

the substance is soft or flexible
like was, flows when it is warmed

Question 34

3 why do some substances conduct electricity

Answer 34

charged particles that are free to move

Question 35

3 when do metals conduct electricity

Answer 35

in solid and liquid states
delocalised electrons are free to move through the lattice

Question 36

3 when do simple, and polymer molecules, substances with a giant covalent structure conduct electricity

Answer 36

they don’t as they have no delocalised electrons

Question 37

3 when do ionic compounds conduct electricity

Answer 37

contain oppositely charge ions
free to move when in liquid or dissolved states and solvents
NOT when solid
conduct when molten or in solution