Ch 4 - Metallic Bonding

Question 1

what is metallic bonding?

Answer 1

attraction between the ‘sea of delocalised electrons’ and the positive ions

Question 2

which groups are involved?

Answer 2

occurs between metals (group 1,2,3 and transition metals)

Question 3

how does it work?

Answer 3

the metal loses its outer shell electron(s) to form the positive metal ion

electrons are delocalised into the space between the positive metal ions - this is the ‘sea of delocalised electrons’

delocalised electrons are free to move

Question 4

can metallicly bonded substances conduct electricity and heat? why?

Answer 4

yes

delocalised electrons are free to move

Question 5

what is an alloy?

Answer 5

mixture of metals (two or more)

Question 6

what are some examples of alloys?

Answer 6

brass = copper and zinc

steel = iron, zinc and carbon

Question 7

how can metals be made harder?

Answer 7

by alloying them

(this is the main purpose of alloys)

Question 8

are atoms in alloys different sizes or the same?

Answer 8

different

Question 9

what happens as a result of atoms in alloys being different sizes?

Answer 9

this disrupts regular packaging

makes it difficult for particles to slide over each other when a force is applies

Question 10

what are some uses of copper?

Answer 10

sauce pans

water pipes

electrical wires

door handles

power lines

Question 11

what are some examples of alloys’ uses?

Answer 11

coins

furniture

car wheels

ships

buildings

Question 12

what structure do metallic bonds form?

Answer 12

giant metallic structure

Question 13

what is the giant metallic structure

Answer 13

Regular array of positive ions and ‘sea of delocalised electrons’

held together by the attraction between the two

Question 15

do metals tend to be strong or weak? high or low melting and boiling points?

why?

Answer 15

strong

high

because of the powerful attractions between them

Question 16

are metals good or bad conductors of electricity? why?

Answer 16

good

because the delocalised electrons are free to move through the structure

Question 17

how do metals conduct electricity?

Answer 17

Question 18

are metals good or bad conductors of heat? why?

Answer 18

good

because delocalised electrons are free to move

if you heat one piece of metal, the energy is picked up by the electrons

as they electrons move, the heat energy is transferred throughout the structure

Question 20

which metal is used as a coating to prevent rusting and which property does the use depend?

Answer 20

zinc

more reactive than object it is covering

Question 21

which metal is used as an aircraft body and which property does the use depend?

Answer 21

aluminium

to be strong

Question 22

what are some metals described as being? what does this mean?

Answer 22

elastic

this is when, if it is subject to a small force, it will stretch and then return back to its original shape when the force is released

if a large force is applied, the particles slide over each other and stay in their new positions

Question 23

which metal is used as electrical wiring and which property does the use depend?

Answer 23

copper

to be bent into shape easily

conducts electricity

sacrificaial protection

Question 24

which metal is used as railway tracks and which property does the use depend?

Answer 24

steel

ability to expand

very strong

Question 26

are metals usually bent into shape easily or with difficulty? why?

Answer 26

easily

because their layers slide easily over each other

Question 27

what does malleable mean?

Answer 27

easily beaten into shape

Question 28

what does ductile mean?

Answer 28

easily pulled into wires