Student book answers
Chapter 1
Chemistry C2 Unit Opener
Picture Puzzler:
Key Words
mercury, explosion, test tube, acid, lava
The key word is metal.
Picture Puzzler:
Close up
Banded iron rock with coloured mineral layers.
C2 1.1 Metals and non-metals
In-text questions
A Metals are on the left-hand side and non-metals on the right-hand side of the Periodic
Table.
B poor conductivity of electricity, poor conductivity of heat, dull, low density, brittle, and
not sonorous
C Metal oxides are basic, non-metal oxides are acidic. Most metal oxides are solids at
20 °C, non-metal oxides are usually gases at 20 °C.
Activity
Metal or non-metal?
X is a metal because of its high melting point, electrical conductivity, and basic oxide.
Y is a non-metal due to its low melting point, inability to conduct electricity, and acidic
oxide.
Z is likely to be a metalloid, as it exhibits properties of both metals (conductivity) and
non-metals (reasonably low melting point).
Summary
questions
1 metals: sonorous, good conductors of electricity, high density, malleable, basic oxides
non-metals: low melting points, dull, brittle (8 marks)
2 Element A is likely to be a metal, which means it will be (credit six of the following):
good conductor of electricity, good conductor of heat, shiny, high density, malleable,
ductile, sonorous. (6 marks)
3 QWC question (6 marks). Example answers:
Metals are good conductors of heat and electricity, but non-metals are not. Metals are
shiny, but non-metals are dull. The density of metals is much higher than that of nonmetals. Metals are malleable and ductile, whereas non-metals are brittle. Metals are also
sonorous, whereas non-metals are not.
C2 1.2 Groups and periods
In-text questions
A groups
B periods
Activity
Predictable patterns?
Credit bar charts to show atomic radii of elements in Period 2 and Period 3.
For both periods, atomic radii are larger at the start of the period (Li and Na) than at
the end (F and Cl).
Atomic radii decrease more rapidly at the start of a period than at the end.
Atomic radii for Period 3 are larger than those of Period 2.
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This resource sheet may have been changed from the original.
Student book answers
Chapter 1
Summary
questions
1 groups, periods, down, across (4 marks)
2 Credit suitable bar charts for density data (one for cobalt, rhodium, and iridium,
and another for nickel and platinum). Credit a predicted palladium density of 9–15
g/cm3. The actual density of palladium is 10.4 g/cm3.
(3 marks)
3 Example answers (6 marks):
Vertical columns are called groups. Horizontal rows are called periods. Numerical
data for one element can be predicted given data of surrounding elements. These
elements can be neighbouring elements in periods or groups. Melting points increase
down a group. Atomic radii decrease across a period. The density of elements
increases down a group.
C2 1.3 The elements of Group 1
In-text questions
A Group 1 metals have lower melting points than other metals.
B decreases
C hydrogen
Activity
Which conclusion?
Credit reasonable explanations that support either Sam’s or Ben’s theory.
A more detailed description of the pattern may be: The density of Group 1 metals
increases down the group in a roughly linear fashion. Potassium is an anomaly
because it has a smaller density than that of sodium. Densities of caesium and
francium are required to understand the trend in Group 1 metal densities better.
Summary
questions
1 Any five from:
From top to bottom of Group 1, boiling point decreases.
From top to bottom of Group 1, the vigour of the reaction with water increases.
From bottom to top of Group 1, melting point increases.
All Group 1 elements have low densities.
All Group 1 elements conduct electricity.
All Group 1 elements react with water to make hydrogen and an alkaline solution.
2a Credit appropriate bar chart, with hardness decreasing from Li to Cs. (6 marks)
b Hardness decreases down Group 1. (2 marks)
c 0.4, because hardness decreases by 0.1 for each element down Group 1. (2 marks)
3 QWC question (6 marks). Example answers:
Physical properties down Group 1: decreasing hardness, decreasing melting point,
decreasing boiling point.
Chemical properties down Group 1: increased reactivity with water.
C2 1.4 The elements of Group 7
In-text questions
A Destroy bacteria to make water safe to drink or swim in.
B fluorine, chlorine, bromine, iodine, astatine
C Boiling points increase down Group 7.
D Reactions become less vigorous down the group.
© Oxford University Press 2014 www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original.
Student book answers
Chapter 1
Activity
Better bar charts
Credit correctly drawn bar charts where boiling points increase down Group 7 (from
F to At). Students should offer suggestions on how to improve each other’s bar
charts.
Summary
questions
1 halogens, right, non-metals, increase, less (5 marks)
2 Reactions a, c, and d will happen. In each case the Group 7 element on its own is more
reactive/higher up in Group 7 than the Group 7 element in the compound. A displacement
reaction occurs. (6 marks)
3 QWC question (6 marks). Example answers:
As non-metals, Group 7 elements do not conduct electricity. They have low melting points
that increase down the group. They have low boiling points that increase down the group.
Fluorine and chlorine are gases, but bromine is a liquid and; iodine and astatine are solids.
Reactivity of Group 7 elements decreases down the group. This means that halogens can
displace metal halides in chemical reactions.
C2 1.5 The elements of Group 0
In-text questions
A helium, neon, argon, krypton, xenon, and radon
B Boiling points increase down Group 0.
C Takes part in very few reactions.
Activity
Using Group 0
Credit suitable eye-catching and persuasive adverts about the merits of using Group
0 elements or compounds in the correct product.
For example, neon in advertising signs, helium in balloons, argon as insulating gas
between the layers in double glazing, or krypton in lasers.
Summary
questions
1 The noble gases are all in Group 0 of the Periodic Table. The element at the top
of the group is helium.
The noble gases are non-metals. They have very few reactions. From bottom to
top of the group, boiling point decreases. (5 marks)
2 Melting point increases down Group 0. Credit predictions for the melting point of
argon between –180 and –220 ºC. (The melting point of argon is –189.4 ºC.)
3 Song or rap must include six of the following (6 marks):
Melting point increases down Group 0.
Boiling point increases down Group 0.
They are all colourless gases at room temperature.
They glow brightly when high-voltage electricity passes through them.
They are all very unreactive.
They are found in the atmosphere, mixed with other gases.
Helium can be found with natural gas underground or under the sea.
© Oxford University Press 2014 www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original.
Student book answers
Chapter 1
C2 Chapter 1 summary
End-of-chapter
questions
1a Going down the group from titanium to hafnium, melting point increases. (2 marks)
b 1850 °C (2 marks)
2a Mendeleev left gaps for elements he predicted should exist, but that had not yet been
discovered. (1 mark)
b Mendeleev predicted a low melting point for the missing element, and was correct in
this prediction, since 30 °C is a low melting point for a metal. (2 marks)
c So that he could find the mean value. This value is more likely to be accurate than the
value obtained from one measurement. (1 mark)
d (30.14 + 30.16 + 30.14 + 30.15 + 30.16 + 30.16) ÷ 6 = 30.15 °C (1 mark)
e Mendeleev predicted a density of 6.0 g/cm3, and Boisbaudran measured a value of 4.7
g/cm3. Boisbaudran probably decided to do the experiment again because his value was
not close to that predicted by Mendeleev. (2 marks)
3 This is a QWC question. Students should be marked on the use of good English,
organisation of information, spelling and grammar, and correct use of specialist scientific
terms. The best answers will provide a detailed comparison
between patterns in properties of Group 1 and Group 7 elements (maximum of 6 marks).
Examples of correct scientific points:
Going down Group 1, the elements become more reactive.
For example, the reactions with water become more vigorous.
Going down Group 7, the elements become less reaction.
For example, the reactions with iron become less vigorous.
These patterns also apply to the reactions with oxygen and with displacement reactions.
Melting points decrease going down Group 1.
On the other hand, melting points increase going down Group 7.
© Oxford University Press 2014 www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original.
Student book answers
Chapter 1
Answer guide for Maths Challenge
Developing
1–2 marks
Secure
3–4 marks
 One or both bar charts include
element names on the x-axis.
 One Y-axis labelled correctly,
but units not included.
 Uneven scales on y-axes on both
bar charts.
 Some bars drawn accurately
on both bar charts.
 Sentence such as Going down
 One or both bar charts include
element names on the x-axis.
 Y-axis on one bar chart
labelled density, but
units missing.
 Y-axis on other bar chart
labelled boiling point, but
units missing.
Extending
5–6 marks
 Both bar charts include
element names on the x-axis.
 Y-axis on one bar chart
labelled density (g/cm3).
 Y-axis on other bar chart
labelled boiling point (°C).
 Even scales on y-axes on both
bar charts.
Group 3, density increases or
 Even scales on y-axes on both
bar charts.
 Bars plotted accurately on both
bar charts.
Going down Group 3, boiling
 Most bars plotted accurately
 Sentence such as ‘Going down
point decreases.
on both bar charts.
 One or two sentences such as
Going down Group 3, density
group 3, density increases for
the first three elements’.
 Several sentences such as Going
increases or Going down
down Group 3, boiling point
Group 3, boiling point decreases.
decreases. At the top, boron has
the highest value of 3930 °C, and
at the bottom thallium has the
lowest value of 1460 °C.
© Oxford University Press 2014 www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original.