Noble Gases (Cambridge (CIE) O Level Chemistry): Exam Questions

Exam code: 5070

1 hour28 questions
1
1 mark

Element X is an unreactive non-metal element. Where could this element be found on the Periodic table?

  • At the far left hand side

  • At the far right hand side

  • At the top of Group VI

  • At the bottom of Group VII

2
1 mark

Argon is a noble gas in Group VIII.

Which is the correct formula for argon gas?

  • Ar

  • Ar2

  • Ar3

  • Ar-

3
1 mark

Krypton is a noble gas.

How many atoms are joined together in one particle of krypton gas?

  • 1

  • 2

  • 4

  • 8

4
1 mark

Welding is carried out under argon to keep air away from the hot metal.

Which statement explains why the argon itself does not react with the hot metal?

  • Its outer shell of electrons is empty.

  • Its outer shell of electrons is complete.

  • Its atoms are joined together in pairs.

  • Its atoms gain electrons from the metal.

5
1 mark

The formulae of four gases are shown.

Cl2 He N2 O2

Which formula is that of a noble gas?

  • Cl2

  • He

  • N2

  • O2

1
1 mark

Which row describes the properties of a typical noble gas?

 

outer electrons

atom or molecule

boiling point

A

full

atom

very low

B

6

molecule

low

C

8

atom

very high

D

6

molecule

high

    2
    1 mark

    Which diagram shows a mixture of noble gases?

    Four particle diagrams labelled A, B, C and D.

A: Single white circles and pairs of touching black circles present; no white–black bonds.
B: Some black–white pairs present; also separate black circles.
C: Black–white pairs and groups of three particles (one black, two white) bonded together.
D: Separate black and white circles only; no particles bonded.
      3
      1 mark

      A student is asked to explain why argon is unreactive.

      The student writes:

      argon has a stable octet

      The mark is not awarded.

      What is missing from the student's answer?

      • that argon is a gas at room temperature

      • that argon has eight protons

      • that the eight electrons are in the outer shell

      • that argon has eight neutrons

      4
      1 mark

      Chemists have succeeded in making a small number of compounds of xenon, such as XeF4.

      The noble gases are still described as unreactive.

      Which statement explains why this description is still used?

      • Xenon is not a noble gas.

      • XeF4 is a mixture rather than a compound.

      • A xenon atom does not have a complete outer shell.

      • A complete outer shell leaves very little tendency to gain, lose or share electrons, so reactions are very difficult.

      5
      1 mark

      Sodium forms the chloride NaCl and magnesium forms the chloride MgCl2.

      Neon forms no chloride at all.

      Which statement explains why?

      • A neon atom has a complete outer shell, so it has no electrons to lose and no space to gain any.

      • Neon has more protons than chlorine.

      • Neon has more electrons than chlorine.

      • Neon is a gas and chlorine is a gas.

      1
      1 mark

      Which statement about the Group VIII noble gases is correct?

      • They all have eight electrons in their outer shell.

      • Their outer shell holds as many electrons as it is able to hold.

      • They all have two electrons in their outer shell.

      • They all have eight electrons in total.

      2
      1 mark

      The noble gases exist as single atoms rather than as molecules.

      Which statement explains why?

      • Their atoms already hold the maximum number of outer electrons, so sharing would gain them nothing.

      • They are gases, and gases are made of single atoms.

      • Their atoms are too small to share electrons with each other.

      • Their atoms repel one another.

      3
      1 mark

      The relative atomic mass of argon is 40.

      A student states that the relative molecular mass of argon gas is 80.

      What is the error in the student's statement?

      • The relative atomic mass of argon is 20, not 40.

      • The student should have divided by 2 rather than multiplied.

      • Argon exists as single atoms, so it has no relative molecular mass.

      • There is no error in the statement.

      4
      1 mark

      Argon is unreactive.

      Which statement gives the reason for this?

      • Argon has 22 neutrons and 18 protons.

      • Argon's outer shell is further from the nucleus than neon's outer shell.

      • Argon has 18 electrons in total.

      • Argon's outer shell is complete.

      5
      1 mark

      Sodium forms Na+ ions and chlorine forms Cl- ions.

      Argon forms neither Ar+ nor Ar- ions.

      Which statement explains why?

      • Argon has no outer shell electrons to lose.

      • Argon's outer shell is already complete, so losing or gaining an electron would break that arrangement.

      • Argon atoms are neutral and cannot become charged.

      • Argon is in Group VIII, and Group VIII elements have no charge.