O LevelChemistryCambridge (CIE)Exam Questions2. Atoms, Elements & Compounds2.3 Isotopes

Isotopes (Cambridge (CIE) O Level Chemistry): Exam Questions

Exam code: 5070

2 hours32 questions

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2.3 Isotopes

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1
1 mark

The atomic structure of atoms Q, R, S and T are shown in the table.

Atom

Number of protons

Number of neutrons

Number of electrons

Q

6

7

6

R

7

7

7

S

6

8

6

T

8

8

8

Which two atoms are isotopes?

A

Q and S

B

Q and T

C

R and T

D

R and S

    Choose your answer

    2
    1 mark

    An atom of calcium is represented as Ca2040

    Which atom is an isotope of this atom?

    • Ar1838

    • Ar1840

    • Ca2042

    • Ti2246

    Choose your answer

    3
    1 mark

    Chlorine has two isotopes, 35Cl and 37Cl.

    The two isotopes have identical chemical properties.

    Why is this?

    • They have the same electronic configuration.

    • They have the same nucleon number.

    • They have the same number of neutrons.

    • They have the same relative atomic mass.

    Choose your answer

    4
    1 mark

    An atom contains 9 protons, 10 neutrons and 9 electrons.

    Which symbol represents this atom?

    • F910

    • F919

    • Ne1019

    • F928

    Choose your answer

    5
    1 mark

    An atom of argon, 40Ar, and an atom of calcium, 40Ca, both have a nucleon number of 40.

    These two atoms are not isotopes of each other.

    Which statement explains why?

    • Isotopes must contain equal numbers of protons and neutrons.

    • Isotopes must contain the same number of neutrons.

    • Isotopes must contain the same number of nucleons.

    • Isotopes must contain the same number of protons.

    Choose your answer

    1
    1 mark

    Two isotopes of chlorine are 35Cl and 37Cl.

    Using these isotopes, how many different relative molecular masses are possible for the compound with molecular formula C2H3Cl3?

    • 2

    • 3

    • 4

    • 5

    Choose your answer

    2
    1 mark

    The table shows the percentage abundance of the three isotopes of element Z.

    Isotope

    24Z

    25Z

    26Z

    Percentage abundance

    79%

    10%

    11%

    What is the relative atomic mass of Z?

    • 24.0

    • 24.1

    • 24.3

    • 25.0

    Choose your answer

    3
    1 mark

    The relative atomic mass of element X is 63.5.

    X has only two isotopes, 63X and 65X.

    Which statement about a sample of X is correct?

    • Every atom of X has a mass of 63.5.

    • There are equal numbers of 63X atoms and 65X atoms.

    • There are more 63X atoms than 65X atoms.

    • There are more 65X atoms than 63X atoms.

    Choose your answer

    4
    1 mark

    The table shows the numbers of protons, neutrons and electrons in four particles.

    particle

    number of protons

    number of neutrons

    number of electrons

    1

    20

    20

    20

    2

    20

    20

    18

    3

    20

    22

    20

    4

    22

    22

    22

    Which two particles are isotopes of the same element?

    • 1 and 2

    • 1 and 3

    • 1 and 4

    • 2 and 4

    Choose your answer

    5
    1 mark

    Aluminium has only one naturally occurring isotope, Al1327

    How many neutrons are there in an atom of Al1327, and how many electrons are in its second shell?

    • 13 neutrons and 3 electrons

    • 13 neutrons and 8 electrons

    • 14 neutrons and 3 electrons

    • 14 neutrons and 8 electrons

    Choose your answer

    6
    1 mark

    Two atoms, X and Y can be represented as shown

    X37              Y38

    Which statement is correct for both atoms?

    • They have the same chemical properties because they have the same number of neutrons.

    • They have the same chemical properties because they have the same number of electrons in their outer shell.

    • They have the same physical properties because they have the same number of electrons in their outer shell.

    • They have the same physical properties because they have the same number of protons.

    Choose your answer

    1
    1 mark

    Which row correctly describes the number of outer shell electrons and properties of isotopes?

    Number of outer shell electrons

    Chemical properties

    A

    same

    same

    B

    same

    different

    C

    different

    same

    D

    different

    different

      Choose your answer

      2
      1 mark

      Iridium has two isotopes, 191Ir and 193Ir. Calculate the relative atomic mass of iridium using the data given:

      Mass number

      191

      193

      Percentage abundance 

      62.7%

      37.3%

      • 191.0

      • 191.7

      • 192.0

      • 192.3

      Choose your answer

      3
      1 mark

      An element has two isotopes. One isotope has a relative mass of x and the other has a relative mass of x + 2.

      In a sample of this element, 25% of the atoms have a relative mass of x.

      What is the relative atomic mass of the element?

      • x + 0.5

      • x + 1

      • x + 1.5

      • x + 2

      Choose your answer

      4
      1 mark

      Element J has two isotopes, 204J and 209J.

      The relative atomic mass of J is 205.0

      What percentage of the atoms in a sample of J are 209J?

      • 20%

      • 25%

      • 50%

      • 80%

      Choose your answer

      5
      1 mark

      The symbols for two particles are shown.

      {}_{35}^{81}\text{Br}{}^{-}

      Kr3684

      Which statement is correct?

      • They are isotopes of the same element.

      • They contain the same number of electrons.

      • The bromide ion contains more electrons than the krypton atom.

      • The bromide ion contains more protons than the krypton atom.

      Choose your answer

      6
      1 mark

      Copper has two naturally occurring isotopes, 63Cu and 65Cu. The relative abundance of 63Cu is 69%.

      What is the relative atomic mass of copper?

      • 63.6

      • 64.0

      • 64.4

      • 65.0

      Choose your answer