Bonding | OCR Gateway GCSE Chemistry Structured Questions 2018

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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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 $□$

B $□$

C $□$

D $□$

Explain your answer.

[2]

ii)

What is meant by physical property?

[1]

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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.

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1c

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.

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, C

l

₂, reacts with barium, Ba.

Barium chloride, BaC

l

₂, 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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1a5 marks

This question is about structure and bonding.

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

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]

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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.

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.

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2b1 mark

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

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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	$□$
Gallium	$□$
Germanium	$□$
Technetium	$□$

[1]

ii)

Give two reasons for your answer to (c)(i).

[2]

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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.

{}_{10}^{20}{Ne}

{}_{10}^{22}{Ne}

Complete Table 23.3 to show the number of protons, neutrons and electrons in each neon isotope.

	${}_{10}^{20}{Ne}$	${}_{10}^{22}{Ne}$
Proton
Neutron
Electron

Table 23.3

[3]

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	Download	View
Easy
Medium
Hard

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

OCR Gateway GCSE Chemistry

Topic Questions

2.2 Bonding

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