METALLIC BONDING PRACTICE
Q1. This picture shows a sword. The sword is about 3400 years old. It is made of an alloy called
bronze.
Photograph © O.Louis Mazzatenta / Getty Images
Bronze is made from copper and tin.
Bronze made better swords than pure copper. This is because bronze is harder than pure
copper.
Explain why bronze is harder than pure copper.
Your answer should include details of:
• how the atoms are arranged in pure copper and bronze
• why pure copper is relatively soft
• why bronze is harder.
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
(Total 4 marks)
Q2. The picture shows a copper kettle being heated on a camping stove.
Copper is a good material for making a kettle because:
•
it has a high melting point
•
it is a very good conductor of heat.
(a)
Explain why copper, like many other metals, has a high melting point.
You should describe the structure and bonding of a metal in your answer.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(4)
Q3. By reference to their structure, explain how the particles in a piece of metal are held together
and how the shape of the metal can be changed without it breaking.
(You may use a diagram in your answer.)
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(b)
Explain why metals are good conductors of electricity and suggest why this conductivity
increases across the periodic table from sodium to magnesium to aluminium.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 9 marks)
Q4. The diagram shows a model of part of the giant lattice of a metal.
(a)
Name particles X and Y.
X .....................................................
Y .....................................................
(2)
(b)
Explain, in terms of the giant structure above, why is it possible to bend a piece of metal.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Q5. Iron is used (as steel) to make the body panels for cars.
The iron panels have to be bendable so that they can be pressed into the shape required, but
must also be strong. The panels must also be able to conduct electricity because they form part
of the electrical circuits of the car.
(a)
Iron is a typical metal. Describe the structure and bonding in a metal such as iron. You
may use a diagram if you wish.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(b)
Explain how the structure and bonding of iron:
(i)
allows the body panels to conduct electricity;
...........................................................................................................................
(2)
(ii)
allows the body panels to be bent into shape;
...........................................................................................................................
(1)
(iii)
gives the body panels strength.
...........................................................................................................................
(1)
(Total 8 marks)
Q6. The diagram shows the arrangement of atoms in an alloy.
(a)
What is meant by an alloy?
................................................................................................................................
................................................................................................................................
(2)
(b)
Name the alloy represented in the diagram.
................................................................................................................................
(1)
(c)
Give one advantage of using this alloy instead of pure iron.
................................................................................................................................
................................................................................................................................
(1)
(d)
Which elements are used to make brass?
................................................................................................................................
(1)
(Total 5 marks)
Q7. By reference to their structure, explain how the particles in a piece of metal are held together
and how the shape of the metal can be changed without it breaking.
(You may use a diagram in your answer.)
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(b)
Explain why metals are good conductors of electricity and suggest why this conductivity
increases across the periodic table from sodium to magnesium to aluminium.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 9 marks)
METALLIC BONDING MS
Q1. in pure copper the atoms are arranged in layers
accept a correct diagram
1
therefore copper is soft because copper atoms can slide over each other
1
in bronze the tin atoms disrupt / distort the structure
accept a correct diagram
1
therefore bronze is harder than copper because the metal atoms
cannot slide over each other
Q2. any four from:
max 3 marks if any reference made to covalent / ionic bonding /
molecules or intermolecular forces or graphite / diamond or forces
of attraction between electrons and then ignore throughout
•
giant structure / lattice
ignore layers
•
positive ions
•
sea of electrons or delocalised / free electrons
ignore electrons can move
•
awareness of outer shell / highest energy level electrons are involved
•
(electrostatic) attractions / bonds between electrons and positive ions
•
bonds / attractions (between atoms/ ions) are strong
allow hard to break for strong
ignore forces unqualified
•
a lot of energy / heat is needed to break these bonds / attractions
ignore high temperature
4
(b)
(i)
that they are very small
accept tiny / really small / a lot smaller / any indication of very
small
eg microscopic, smaller than the eye can see
or
1–100 nanometres or a few (hundred) atoms
ignore incorrect numerical values if very small is given
1
(ii)
any 2 from:
•
one (non-bonded) electron from each atom
•
delocalised / free electrons
allow sea of electrons
ignore electrons can move
•
electron carry / form / pass current / charge
ignore carry electricity
2
[7]
Q3. Idea that
the electrons do not belong to specific atoms/delocalised electrons
[credit if done on appropriate diagram]
metal atoms form positive ions
the attraction which exists between particles with opposite charges, holds the metal together
no specific bonds exist between adjacent atoms/ions
atoms/ions can slide over each other so allowing metals to bend
each for 1 mark
5
(b)
some electrons in the structure are delocalised/free to move
for 1 mark
these free electrons carry the electric current
for 1 mark
from left to right across the period, atoms of elements have
more free electrons
gains 1 mark
but from left to right across the period, atoms of elements have more free
electrons because they have more electrons in the outer shells
gains 2 marks
4
[9]
Q4. X – (metal) atom / ion
1
Y – electron
1
(b)
free electrons or electrons move
1
(allow metal) atoms / ions to slide over each other
OR
bonding non - directional for 2 marks
1
[4]
Q5. some electrons from outer shells
(some electrons) free to move/mobile
through whole structure/between atoms/sea of electrons
hold atoms together
for 1 mark each
or positive ions in a sea of electrons (owtte)
2 marks
atoms in regular structure/layers
giant structure
close packed
credit diagrams – look for labels
for 1 mark each any 4
4
(b)
(i)
electrons,
free to move (reference to electrons)
for 1 mark each
2
(ii)
layers/atoms can slide over each other
for 1 mark
1
(iii)
free electrons hold atoms strongly together/strong forces of attraction/bonds
(between atoms)/tight packing of atoms
for 1 mark
1
[8]
Q6. mixture
not compound
1
of a metal with other element(s) / metals
not of elements
not of a metal with other substances
1
(b)
steel
allow stainless steel
1
(c)
stronger / increased strength / harder / less malleable / less brittle
not corrosion / rusting
1
(d)
copper and zinc
1
[5]
Q7. Idea that
the electrons do not belong to specific atoms/delocalised electrons
[credit if done on appropriate diagram]
metal atoms form positive ions
the attraction which exists between particles with opposite charges, holds the metal together
no specific bonds exist between adjacent atoms/ions
atoms/ions can slide over each other so allowing metals to bend
each for 1 mark
5
(b)
some electrons in the structure are delocalised/free to move
for 1 mark
these free electrons carry the electric current
for 1 mark
from left to right across the period, atoms of elements have
more free electrons
gains 1 mark
but from left to right across the period, atoms of elements have more free
electrons because they have more electrons in the outer shells
gains 2 marks
4
[9]