B London dispersion forces - Uddingston Grammar School

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Uddingston Grammar School
CfE Higher Chemistry
Unit 1: Chemical Changes and Structure
Sub-Topic C: Structure and Bonding
Homework 5: Elements 1-20 Bonding and Structure
1. Which of the following elements exists as discrete molecules?
A
B
C
D
Neon
Carbon (diamond)
Silicon
Phosphorus
2. Which of the following structures is never found in compounds?
A
B
C
D
Ionic
Monatomic
Covalent network
Covalent molecular
3. Which of the following does not contain covalent bonds?
A
B
C
D
Chlorine gas
Argon gas
Oxygen gas
Carbon ( fullerene )
4. Diamond has
A
B
C
D
an ionic lattice structure
a covalent network structure
covalent molecules linked by London dispersion forces
covalent sheets with only London dispersion forces acting between sheets
5. Which type of bonding is never found in elements?
A
B
C
D
Metallic
London dispersion forces
Polar covalent
Non-polar covalent
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6. Element X was found to have the following properties.
(i) It does not conduct electricity when solid.
(ii) It forms a gaseous oxide.
(iii) It is a solid at room temperature.
Element X could be
A
magnesium
B
silicon
C
nitrogen
D
sulphur
7.
What type of bonding and structure is found in a fullerene?
A
B
C
D
Ionic molecular
Metallic network
Covalent network
Covalent molecular
8. At room temperature, a solid substance was shown to have a lattice
consisting of positively charged ions and delocalised outer electrons. The
substance could be
A
B
C
D
diamond
potassium
mercury
sulphur
9. Which of the following elements is most likely to have a metallic lattice
structure?
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10. Which of the following elements exists as a covalent network ?
A
B
C
D
Neon
Sulphur
Silicon
Phosphorus
11. Information about four elements from the third period of the Periodic Table
is shown in the table.
(a) Complete the table to show the bonding and structure for each element.
2
(b) Why is there a decrease in the size of atoms across the period from
aluminium to sulphur?
1
(c) Argon is also in the third period. Argon is a very useful gas and each year
750 000 tonnes of argon are extracted from liquid air.
(i) Suggest how argon could be extracted from liquid air.
1
(ii) Air contains 1·3% argon by mass. Calculate the mass of liquid air needed to
obtain 750 000 tonnes of argon.
1
(iii) Argon is used in the manufacture of magnesium powder. A jet of liquid
argon is blown at a stream of molten magnesium producing fine droplets
of metal. These cool to form the powder.
Why can liquid air not be used to make magnesium powder?
1
(iv) Argon was discovered in 1890’s when samples of nitrogen prepared by
different methods were compared. The element name was derived from
the Greek argos, which means “lazy one”.
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(v)
Two samples of nitrogen can be prepared as shown.
Method 1 Removing carbon dioxide and oxygen from the air.
Method 2 Reaction of sodium nitrite with ammonium chloride.
Using your knowledge of chemistry, comment on the discovery and naming of argon.
3
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12. Copy and complete the table below by adding the name of an element for
each of the types of bonding and structure described.
2
13. The elements in the second row of the Periodic Table are shown below.
Li
a)
Be
B
C
N
O
F
Ne
Why does first ionisation energy increase on crossing the period from lithium to
neon?
1
b)
Diamond and graphite are forms of carbon that exist as network solids.
Name a form of carbon that exists as discrete molecules.
1
c)
Use the electronegativity values to explain why nitrogen chloride contains pure
covalent bonds.
1
d)
Name the element which would be described as having a monatomic structure. 1
TOTAL: 25 MARKS
5
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