Bonding (OCR Gateway GCSE Chemistry: Combined Science)

Exam Questions

1 hour35 questions
12 marks

Methane has the formula, CH4.

Look at the representations of methane.

q23-paper-1-specimen-2016-ocr-gcse-chemistry

Describe the limitations of a displayed formula.

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1a5 marks

This question is about structure and bonding.

Look at the two structures, A and B, in Fig. 22.1.

fig-22-1-paper-1-nov-2020-ocr-gcse-chem

i)
Identify the bonding in structure A.

Explain your answer.

Bonding ..............................................................................

Explanation .......................................................................

[2]

ii)
Explain why structure B has a high melting point.

[2]

iii)
Explain why structure B does not conduct electricity.

[1]

1b2 marks

Look at the structure of a metal in Fig. 22.2. Metals are malleable, which means they can be hammered or pressed into shape without breaking or cracking.

fig-22-2-paper-1-nov-2020-ocr-gcse-chem

Explain why metals are malleable.

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2a2 marks

Dmitri Mendeleev produced a Periodic Table of elements which is the basis for our modern Periodic Table. He left gaps for elements that had not been discovered yet as shown in Fig. 23.1.

fig-23-1-paper-1-nov-2020-ocr-gcse-chem

Describe two ways Mendeleev arranged the elements in his Periodic Table.

2b1 mark

Describe how the elements are arranged in the modern Periodic Table.

2c3 marks

Mendeleev left gaps in his Periodic Table for undiscovered elements. He predicted properties of these elements.

Table 23.1 shows the predicted properties for one of these elements in one of the gaps.

Mendeleev called this element ‘eka-silicon’.

Appearance Grey metal
Melting point (°C) Over 800
Relative atomic mass 72
Density (g / cm3) 5.5

Table 23.1

Table 23.2 shows some of the elements that were discovered after Mendeleev published his Periodic Table.

  Scandium (Sc) Gallium (Ga) Germanium (Ge) Technetium (Tc)
Appearance Silver-white metal Silver-blue metal Grey-white metal Grey metal
Melting point (°C) 1541 30 947 2157
Relative atomic mass 45.0 69.7 72.6 98.0
Density (g / cm3) 3.0 5.9 5.35 11.0

Table 23.2

i)
Which element matches Mendeleev’s predictions for ‘eka-silicon’?

Tick (✓) one box.

Scandium   square
Gallium square
Germanium square
Technetium square

[1]

ii)
Give two reasons for your answer to (c)(i).
[2]
2d5 marks
i)

Mendeleev did not predict the existence of argon, neon, krypton or xenon.

The electron arrangement of argon is 2,8,8.

What does this tell you about the reactivity of argon?

Explain your answer.

 [2]

ii)
Neon is an element that has isotopes. Two of the isotopes are shown below.

begin mathsize 14px style Ne presubscript 10 presuperscript 20 end style        Ne presubscript 10 presuperscript 22
 
Complete Table 23.3 to show the number of protons, neutrons and electrons in each neon isotope.

  begin mathsize 14px style Ne presubscript 10 presuperscript 20 end style begin mathsize 14px style Ne presubscript 10 presuperscript 22 end style
Proton    
Neutron    
Electron    

Table 23.3

[3]

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33 marks

Look at the diagram.

It shows part of Mendeleev’s Periodic Table which was developed in 1871.

Mendeleev arranged the elements in order of relative atomic mass.

Group 1 2 3 4 5 6 7  
Periods                
1 H
1.008
             
2 Li
6.939
Be
9.012
B
10.81
C
12.011
N
14.007
O
15.999
F
18.998
 
3 Na
22.99
Mg
24.31
Al
29.98
Si
28.09
P
30.974
S
32.06
Cl
35.453
 
4 K
39.102
Ca
40.08
    As
74.92
Se
78.96
Br
79.909
 
5 Rb
85.47
Sr
87.62
In
114.82
Sn
118.69
Sb
121.75
Te
127.60
I
126.90
 
6 Cs
132.90
Ba
137.84
Tl
204.37
Pb
207.19
Bi
208.98
     

Describe the differences between Mendeleev’s Periodic Table and the modern-day version.

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1a3 marks

Metal elements and non-metal elements have different physical properties.

The table shows the physical properties of some elements.

Element Melting point (°C) Density (g/cm3) Electrical conductivity Thermal conductivity Cost
A high high good good high
B low low good poor high
C high low good good low
D high high poor poor low

i)
Which element, A, B, C or D, would be best to use for cables in overhead pylons to transfer electricity?

Tick (✓) one box.

A    square

B    square

C    square

D    square

Explain your answer.

[2]

ii)
What is meant by physical property?

[1]

1b3 marks

Element C burns in oxygen to make white clouds of its oxide.

Describe how you could test the oxide to find out if the element is a metal.

1c
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5 marks

Higher Only 

i)
Chlorine is a non-metal.

Chlorine has two common isotopes.

Look at the information about the common isotopes of chlorine.

q19ci-paper-3-june-2019-ocr-gcse-chem
Complete the table to show the atomic structure for each isotope of chlorine.

Isotope Number of
protons
Number of
neutrons
Number of
electrons
Chlorine-35 ............................... ............................... ...............................
Chlorine-37 ............................... ............................... ...............................
[2]
ii)
Chlorine gas, Cl2, reacts with barium, Ba.

Barium chloride, BaCl2, is made.

Write a balanced half equation for chlorine in this reaction.
[1]
iii)
Barium chloride solution reacts with sodium sulfate solution, Na2SO4.

A white precipitate of barium sulfate, BaSO4, is made.

Write a balanced ionic equation to show the formation of barium sulfate.

Include state symbols.
[2]

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