International ASChemistryEdexcelExam Questions1. Structure, Bonding & Introduction to Organic ChemistryAtomic Structure

Atomic Structure (Edexcel International AS Chemistry): Exam Questions

Exam code: XCH11

36 mins22 questions

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Atomic Structure

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1
1 mark

Which statement about the structure of an atom is correct?

  • The nucleus is large and positive, and electrons fill the space around it

  • The nucleus is large and neutral, and electrons fill the space around it

  • The nucleus is small and neutral, and most of the atom is empty space

  • The nucleus is small and positive, and most of the atom is empty space

Choose your answer

2
1 mark

Which statement about isotopes is not correct?

  • A silicon-30 atom contains 14 protons

  • A magnesium-26 atom contains 14 neutrons

  • Isotopes contain different numbers of protons

  • A carbon-14 atom contains two more neutrons than a carbon-12 atom

Choose your answer

3
1 mark

Which row shows the numbers of protons, neutrons and electrons in a 55Mn2+ ion?

Protons

Neutrons

Electrons

A

25

30

23

B

25

30

27

C

25

55

23

D

30

25

28

    Choose your answer

    4
    1 mark

    In a mass spectrometer, ions are deflected by a magnetic field.

    Which of these species is deflected the most?

    • 35Cl+

    • 35Cl2+

    • 37Cl

    • 37Cl+

    Choose your answer

    5a
    1 mark

    The diagram shows a mass spectrometer.

    Mass spectrometer diagram: a sample enters the ionisation region R, with a positive electrode and electron source, then ions pass through S, curve through magnetic field T and reach the detector; a vacuum pump is shown.

    Which process occurs in region R?

    • the sample is vaporised using a heater

    • electrons are removed from molecules or atoms and positive ions are formed

    •  electrons are added to the molecules or atoms and negative ions are formed

    • ions are accelerated by an electric field

    Choose your answer

    5b
    1 mark

    Which statement is correct for region T?

    • ions with a greater mass have a smaller deflection

    • ions with a greater mass have a greater deflection

    • ions with a greater charge have a smaller deflection

    •  ions are speeded up by a magnetic field

    Choose your answer

    6
    1 mark

    Which of these atoms has the most neutrons?

    • In49115

    • Sn50124

    • Sb51123

    • Te52124

    Choose your answer

    1
    1 mark

    The numbers of subatomic particles present in four species W, X, Y and Z are given in the table.

    Species

    Number of protons

    Number of neutrons

    Number of electrons

    W

    19

    20

    18

    X

    19

    20

    19

    Y

    20

    20

    18

    Z

    20

    22

    20

    Which of these species are isotopic?

    • W and X

    • W and Y

    • X and Z

    • Y and Z

    Choose your answer

    2
    1 mark

    Iodine exists as one isotope with mass number 127.

    Chlorine exists as two isotopes with mass numbers 35 and 37.

    How many molecular ion (ICl3+) peaks are there in the mass spectrum of ICl3?

    • 2

    • 3

    • 4

    • 5

    Choose your answer

    3
    1 mark

    The mass spectrum of a sample of an element has only two peaks.

    Mass spectrum showing relative abundance against m/z: peaks at m/z 191 with relative abundance 25 and m/z 193 with relative abundance 75.

    What is the approximate relative atomic mass of the element in this sample?

    • 191.5

    • 192.0

    • 192.5

    • 193.0

    Choose your answer

    4
    1 mark

    How many protons, neutrons and electrons are present in a 81Br- ion?

    Protons

    Neutrons

    Electrons

    A

    35

    81

    36

    B

    35

    46

    36

    C

    36

    45

    35

    D

    35

    46

    35

      Choose your answer

      5
      1 mark

      A sample of neon contains only the isotopes 20Ne and 22Ne.

      The relative atomic mass of the neon in the sample is 20.2

      What is the percentage of 22Ne atoms in the sample?

      • 0.1%

      • 10%

      • 20%

      • 90%

      Choose your answer

      6
      1 mark

      The mass spectrum of a sample of metal Z shows three peaks.

      m / z

      70

      72

      74

      Relative abundance / %

      24.4

      32.4

      43.2

      What is the relative atomic mass of Z, to three significant figures?

      • 71.6

      • 72.0

      • 72.2

      • 72.4

      Choose your answer

      7
      1 mark

      Bromine exists as two isotopes, 79Br (50.7%) and 81Br (49.3%).

      Which statement describes the main molecular ion peaks in the mass spectrum of bromomethane, CH3Br?

      • One peak at m / z 95

      • Three peaks at m / z 94, 96 and 98

      • Two peaks at m / z 94 and 96, in the ratio 1 : 1

      • Two peaks at m / z 94 and 96, in the ratio 3 : 1

      Choose your answer

      8
      1 mark

      Which sequence shows these ions in order of decreasing deflection in a mass spectrometer?

      • 23Na+ > 24Mg+ > 24Mg2+

      • 24Mg2+ > 23Na+ > 24Mg+

      • 24Mg2+ > 24Mg+ > 23Na+

      • 24Mg+ > 23Na+ > 24Mg2+

      Choose your answer

      9
      1 mark

      X is a halogen other than fluorine. It forms a compound with the formula XFn.

      The mass spectrum of XFn shows a single molecular ion peak at m / z 222

      [Ar values: F = 19.0 Br = 79.9 I = 126.9]

      What is the formula of the compound?

      • BrF3

      • BrF5

      • IF5

      • IF7

      Choose your answer

      10
      1 mark

      Three ions are shown.

      35Cl− 31P3− 39K+

      Which of these statements are correct?

      1. All three ions have the same number of electrons

      2. No two of the ions have the same number of neutrons

      3. The 39K+ ion has more protons than neutrons

      • 1, 2 and 3

      • 1 and 2 only

      • 1 and 3 only

      • 2 and 3 only

      Choose your answer

      1
      1 mark

      A sample of strontium contains four isotopes. Some of their abundances are shown.

      Isotope

      84Sr

      86Sr

      87Sr

      88Sr

      Abundance / %

      0.56

      to be found

      to be found

      82.58

      The relative atomic mass of the strontium in the sample is 87.71

      What are the abundances of 86Sr and 87Sr, in that order?

      • 4.00% and 12.86%

      • 6.96% and 9.90%

      • 9.90% and 6.96%

      • 12.86% and 4.00%

      Choose your answer

      2
      1 mark

      The mass spectrum of a sample of chlorine gas, Cl2, shows three molecular ion peaks at m / z = 70, 72 and 74. Chlorine consists of 75% 35Cl and 25% 37Cl.

      What is the ratio of the heights of the peaks at m / z = 70 : 72 : 74?

      • 1 : 1 : 1

      • 3 : 1 : 0

      • 9 : 1 : 0

      • 9 : 6 : 1

      Choose your answer

      3
      1 mark

      The mass spectrum of a sample of element X shows four peaks, at m / z 12, 24, 25 and 26

      Mass spectrum with percentage abundance against m / z from 0 to 50. There is a very small peak at 12, a tall peak at 24 and two short peaks at 25 and 26, with the peak at 26 slightly taller than the peak at 25.

      Only the significant peaks are shown.

      Which of these statements are correct?

      1. The peak at m / z 12 is due to a 24X2+ ion

      2. The peak at m / z 12 is due to an ion with a mass number of 12

      3. The relative atomic mass of X is between 24 and 25

      • 1 only

      • 1 and 3 only

      • 2 and 3 only

      • 1, 2 and 3

      Choose your answer

      4
      1 mark

      A peak at m / z 20 in a mass spectrum is produced by an ion that contains 18 electrons.

      Which ion produces the peak?

      • 40Ar2+

      • 40Ca2+

      • 42Ca2+

      • 20Ne+

      Choose your answer

      5
      1 mark

      The mass spectrum of a sample of silicon shows four peaks.

      m / z

      14.0

      28.0

      29.0

      30.0

      Relative height

      4.6

      92.2

      4.7

      3.1

      What is the relative atomic mass of the silicon in this sample, to three significant figures?

      • 27.5

      • 28.0

      • 28.1

      • 29.0

      Choose your answer