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Chemistry questions, chapter 2
Nama / NameKelas / ClassTarikh / Date

Matter and the Atomic Structure

45 marks. Use Practice to check each answer as you go, or Exam to answer everything against the clock first.

Section A: objective questions

14 marks
Choose the best answer for each question.
1

Question 1

Which statement describes matter?
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C
Matter is anything that has mass and occupies space. A rainbow can be seen but has neither.
For the teacher: Remembering, low difficulty, standard 2.1.1
Textbook p. 24
2

Question 2

Which process changes a solid directly into a gas?
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A
Sublimation is solid to gas without becoming a liquid. Deposition is the reverse.
For the teacher: Remembering, low difficulty, standard 2.1.2
Textbook p. 25
3

Question 3

Which statement is correct about the particles of a liquid?
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D
In a liquid the particles are close together but not orderly, with higher kinetic energy than a solid.
For the teacher: Understanding, low difficulty, standard 2.1.2
Textbook p. 25
4

Question 4

The temperature stays constant while naphthalene melts. Why?
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B
During melting the heat absorbed overcomes the attraction forces, so the kinetic energy and temperature do not rise.
For the teacher: Understanding, medium difficulty, standard 2.1.3
Textbook p. 28
5

Question 5

What is the relative charge of an electron?
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A
An electron has relative charge −1; a proton is +1 and a neutron is 0.
For the teacher: Remembering, low difficulty, standard 2.2.2
Textbook p. 29
6

Question 6

Who discovered the neutron?
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C
James Chadwick discovered the neutral particles, neutrons, in the nucleus.
For the teacher: Remembering, low difficulty, standard 2.2.3
Textbook p. 31
7

Question 7

Which model describes the atom as a positively charged sphere with electrons in it?
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B
Thomson, who discovered the electron, proposed a positive sphere containing electrons.
For the teacher: Understanding, low difficulty, standard 2.2.3
Textbook p. 30
8

Question 8

An aluminium atom has 13 protons and 14 neutrons. What is its nucleon number?
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D
Nucleon number = protons + neutrons = 13 + 14 = 27.
For the teacher: Applying, low difficulty, standard 2.3.2
Textbook p. 33
9

Question 9

A potassium atom has nucleon number 39 and 19 protons. How many neutrons does it have?
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A
Neutrons = 39 − 19 = 20.
For the teacher: Applying, low difficulty, standard 2.3.2
Textbook p. 33
10

Question 10

A chlorine atom has 17 protons and 18 neutrons. How many electrons are in a chloride ion, Cl−?
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C
The atom has 17 electrons and gains 1 to form the ion: 17 + 1 = 18.
For the teacher: Applying, low difficulty, standard 2.3.2
Textbook p. 33
11

Question 11

Magnesium has proton number 12. What is its electron arrangement?
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B
12 electrons: 2 in the first shell, 8 in the second, 2 left in the third: 2.8.2.
For the teacher: Applying, low difficulty, standard 2.3.4
Textbook p. 35
12

Question 12

How many valence electrons does an atom with electron arrangement 2.8.7 have?
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D
Valence electrons are in the outermost shell: 7.
For the teacher: Understanding, low difficulty, standard 2.3.4
Textbook p. 35
13

Question 13

Atoms W, X, Y and Z have proton numbers 6, 6, 11 and 12 and nucleon numbers 12, 13, 23 and 24. Which atoms are isotopes?
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A
W and X have the same proton number (6) but different nucleon numbers, so different numbers of neutrons.
For the teacher: Analysing, medium difficulty, standard 2.4.1
Textbook p. 37
14

Question 14

Copper has 69% 63Cu and 31% 65Cu. What is the relative atomic mass of copper?
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C
(69 × 63 + 31 × 65) ÷ 100 = 6362 ÷ 100 = 63.62, which is 63.6.
For the teacher: Applying, high difficulty, standard 2.4.2
Textbook p. 38

Section B: structured questions

31 marks
Answer all questions. Write your answers in the spaces provided.
15

Question 15

Table 1 shows the melting point and boiling point of substances P, Q and R.
SubstanceMelting point (°C)Boiling point (°C)
P−759
Q114184
R−219−183
[3 marks] (a)State the physical state of P, Q and R at room temperature (25 °C).
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Tick each point you got.
[1 mark] (b)Which substance changes from solid to liquid when heated from 100 °C to 150 °C?
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Tick each point you got.
For the teacher: Understanding, low difficulty, standard 2.1.2
Textbook p. 40
16

Question 16

Diagram 1 shows the heating curve of naphthalene.
Heating curve with points A, B, C and D
Diagram 1
[1 mark] (a)State the physical state of naphthalene between A and B.
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Tick each point you got.
[1 mark] (b)What is the melting point of naphthalene?
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[2 marks] (c)Explain why the temperature does not change from B to C.
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Tick each point you got.
For the teacher: Analysing, medium difficulty, standard 2.1.3
Textbook p. 28
17

Question 17

Table 2 shows the number of protons and neutrons in atoms P and Q (P and Q are not the actual symbols).
AtomProtonsNeutrons
P910
Q1212
[1 mark] (a)What is the nucleon number of P?
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Tick each point you got.
[1 mark] (b)Write the standard representation of Q.
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[2 marks] (c)Write the electron arrangement of P and of Q.
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[1 mark] (d)Atom Q donates 2 electrons to form an ion. How many electrons does the ion have?
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For the teacher: Applying, low difficulty, standard 2.3.3
Textbook p. 34
18

Question 18

Neon (proton number 10) exists naturally as 90% 20Ne and 10% 22Ne.
[1 mark] (a)What are isotopes?
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Tick each point you got.
[2 marks] (b)Compare the number of protons and neutrons in 20Ne and 22Ne.
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[2 marks] (c)Calculate the relative atomic mass of neon.
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For the teacher: Applying, medium difficulty, standard 2.4.2
Textbook p. 38
19

Question 19

Isotopes are used in many fields.
[1 mark] (a)Name the isotope used to kill cancer cells in radiotherapy.
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[1 mark] (b)State one use of carbon-14.
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[1 mark] (c)State one use of sodium-24 in engineering.
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[1 mark] (d)Give one negative effect of using radioactive isotopes on society or the environment.
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For the teacher: Evaluating, low difficulty, standard 2.4.3
Textbook p. 38
20

Question 20

Choose the scientist who proposed each idea about the atom.
[1 mark] (a)The atom is a positively charged sphere with electrons in it.
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Thomson
[1 mark] (b)Electrons move in shells around the nucleus.
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Bohr
[1 mark] (c)The nucleus also contains neutral particles.
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Chadwick
[1 mark] (d)The nucleus is the centre of the atom and holds most of its mass.
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Rutherford
For the teacher: Remembering, low difficulty, standard 2.2.3
Textbook p. 31
21

Question 21

Chen Ling wipes her wound with a cotton swab soaked in alcohol. Her skin feels cool. Explain why.
[2 marks] (a)Explain why the skin feels cool.
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Tick each point you got.
For the teacher: Understanding, medium difficulty, standard 2.1.2
Textbook p. 41
22

Question 22

An atom of aluminium has 13 protons and 14 neutrons. You are asked to draw its atomic structure.
[1 mark] (a)State what you must show in the nucleus.
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[1 mark] (b)Write the electron arrangement and the shells you would draw.
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[1 mark] (c)State the number of valence electrons.
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For the teacher: Creating, high difficulty, standard 2.3.4
Textbook p. 35