11 mark
An atom has no overall charge because there are the same number of:
| ☐ | A | Protons and neutrons | |
| ☐ | B | Protons and electrons | |
| ☐ | C | Neutrons and electrons | |
| ☐ | D | Protons, neutrons and electrons |
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Atomic Structure (Edexcel GCSE Chemistry: Combined Science)
Exam Questions
57 mins11 questions
2a1 mark
This question is about some of the elements in groups 1 and 2 of the periodic table.
The atomic number of lithium is 3.
The mass number of a lithium atom is 7.
Which row of the table shows the number of protons, neutrons and electrons in an atom of lithium-7?
| Number of protons | Number of neutrons | Number of electons | |||
| ☐ | A | 3 | 3 | 4 | |
| ☐ | B | 3 | 4 | 3 | |
| ☐ | C | 4 | 3 | 7 | |
| ☐ | D | 7 | 4 | 3 |
2b1 mark
Lithium, sodium and potassium are in group 1 of the periodic table.
State, in terms of the electrons in their atoms, what the atoms of lithium, sodium and potassium have in common.
2c
2 marks
2 marksMagnesium has atomic number 12.
Magnesium exists as magnesium-24, magnesium-25 and magnesium-26 atoms.
Explain, in terms of protons and neutrons, why these atoms are isotopes of magnesium.
2d2 marks
Magnesium and calcium are in group 2 of the periodic table. They are less reactive than the metals in group 1.
Calcium reacts with water to form calcium hydroxide, Ca(OH)2, and hydrogen, H2.
Ca (s) + 2H2O (l) → Ca(OH)2 (s) + H2 (g)
Describe what would be seen when a piece of calcium is dropped into a container of water.
2e2 marks
Magnesium reacts very slowly with cold water but it reacts faster with steam, H2O, to form magnesium oxide, MgO, and hydrogen.
Write the balanced equation for the reaction between magnesium and steam.
2f2 marks
The electronic configurations of magnesium and calcium are
magnesium 2.8.2
calcium 2.8.8.2
When magnesium and calcium react with water they form positive ions.
Suggest an explanation, in terms of their electronic configurations, why calcium is more reactive than magnesium.
2g3 marks
3 marksA sample of calcium bromide contains 0.2 g calcium and 0.8 g bromine by mass.
Calculate the empirical formula of calcium bromide.
(relative atomic masses: Ca = 40, Br = 80)
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31 mark
Which statement best describes the structure of an atom?
| ☐ | A | A nucleus containing protons and neutrons, surrounded by electrons | |
| ☐ | B | A nucleus containing protons and electrons, surrounded by neutrons | |
| ☐ | C | A nucleus containing electrons and neutrons, surrounded by protons | |
| ☐ | D | A nucleus containing protons, surrounded by neutrons and electrons |
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4a2 marks
An atom of potassium has atomic number 19 and mass number 39.
i)
Give the electronic configuration of this potassium atom.
(1)
ii)
This potassium atom forms the ion K+.
Which row shows the number of protons and the number of neutrons in this potassium ion, K+?
(1)
| number of protons | number of neutrons | |||
| ☐ | A | 19 | 19 | |
| ☐ | B | 19 | 20 | |
| ☐ | C | 20 | 19 | |
| ☐ | D | 20 | 20 |
4b2 marks
Potassium and caesium are in the same group of the periodic table.
Explain, in terms of electrons, why potassium and caesium are in the same group.
4c2 marks
Fluorine boils at –188 °C.
There are forces between fluorine molecules.
Explain, in terms of these forces, why the boiling point of fluorine is low.
4d3 marks
Potassium reacts with fluorine to form potassium fluoride.
Potassium fluoride is a solid.
Complete the balanced equation for this reaction and add the state symbols.
.................K (...........) + F2 (g) → .................KF (...........)
4e1 mark
What are the elements in group 1 of the periodic table called?
| ☐ | A | alkali metals | |
| ☐ | B | fullerenes | |
| ☐ | C | halogens | |
| ☐ | D | noble gases |
4f2 marks
Figure 14 shows the melting points and boiling points of elements in group 7 of the periodic table.
Figure 14
i)
Give, using Figure 14, the boiling point of bromine.
(1)
boiling point of bromine = ..................................... °C
ii)
State which two elements from Figure 14 are solids at room temperature.
(1)
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51 mark
Higher Only
Element Cu has two isotopes. Their mass numbers are 63 and 65.
- Cu- 63 has a percentage abundance of 69.2%
- Cu- 65 has a percentage abundance of 30.8%
Estimate the relative atomic mass of element Cu.
| ☐ | A | Below 63 | |
| ☐ | B | Between 63.5 and 64 | |
| ☐ | C | Between 64 and 64.5 | |
| ☐ | D | Above 64.5 |
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