Choose the correct answer for each question.

1. In which one of the following molecules would you expect the bonding between the atoms tobe the strongest?
   

   1.   ?    Cl2
   2.   ?    F2
   3.   ?    N2
   4.   ?    O2
   5.   ?    H2

2. In which one of the following molecules would you expect the bond length between the atoms to be the shortest?
   

   1.   ?    Br2
   2.   ?    Cl2
   3.   ?    F2
   4.   ?    H2
   5.   ?    N2

3. Which molecule contains a triple bond?
   

   1.   ?    beryllium chloride, BeCl2
   2.   ?    boron trifluoride, BF3
   3.   ?    ethene, C2H4
   4.   ?    nitrogen, N2

4. An element X has two electrons in its outer shell. Element Y has seven electrons in its outer shell.
   What is the formula for the compound formed from the reaction of X with Y?
   

   1.   ?    XY2
   2.   ?    X2Y
   3.   ?    X2Y7
   4.   ?    X7Y2

5. Ammonia reacts with hydrogen iodide to form a white crystalline solid. Which one of the following gives the name, formula and bonding in the solid?
   

   name

   formula

   contains a co-ordinate bond?

   1.   ?    

      ammonia iodide

      NH3I

      no

   2.   ?    

      ammonia iodide

      NH4I

      yes

   3.   ?    

      ammonium iodide

      NH3I

      no

   4.   ?    

      ammonium iodide

      NH4I

      no

6. Which one of the following does not obey the octet rule?
   

   1.   ?    beryllium chloride
   2.   ?    carbon dioxide
   3.   ?    nitrogen
   4.   ?    oxygen

7. Potassium iodide is converted into a system of free ions when it is
   

   1.   ?    finely powdered
   2.   ?    heated above its melting point
   3.   ?    reacted with bromine
   4.   ?    reacted with chlorine

8. Which one of the following does not have a giant covalent structure?
   

   1.   ?    diamond
   2.   ?    graphite
   3.   ?    quartz
   4.   ?    water

9. Which one of the following does not contain a single bond?
   

   1.   ?    ammonia
   2.   ?    ethene
   3.   ?    nitrogen
   4.   ?    water

10. In which one of the following pairs do both compounds contain multiple bonds between atoms?
    
    

    1.   ?    C₂H₄ and CO₂
    2.   ?    SF₆ and H₂S
    3.   ?    BeCl₂ and BCl₃
    4.   ?    CCl₄ and HCl

11. In which one of the following substances is the carbon-carbon bond the shortest?
    
    

    1.   ?    polythene
    2.   ?    benzene
    3.   ?    ethene
    4.   ?    ethane

12. Which molecule does not contain non-bonding electron pairs?
    
    
    

    1.   ?    BF₃
    2.   ?     Cl₂
    3.   ?    CH₄
    4.   ?    HBr

13. Which one of the following substances is most polar?
    

    1.   ?    fluorine
    2.   ?    chloromethane
    3.   ?    hydrogen fluoride
    4.   ?    carbon dioxide

14. Which one of the following atoms does not obey the octet rule in the compound given?
    

    1.   ?    sulphur in SF6
    2.   ?    nitrogen in NH3
    3.   ?    fluorine in BF3
    4.   ?    carbon in CO2

15. In which one of the following series are the elements in order of increasing electronegativity?
    

    1.   ?    Be  Mg  Ca  Sr
    2.   ?    O  S  Se  Te
    3.   ?    F  Cl  Br  I
    4.   ?    Na  Mg  Al  Si

16. In which one of the following salts would you expect the bond to have the greatest ionic character?
    

    1.   ?    KCl
    2.   ?    LiF
    3.   ?    LiCl
    4.   ?    KF

17. Which one of the following statements about water is correct?
    

    1.   ?    The molecule is non-polar.
       
       
    2.   ?    Hydrogen bonds exist between molecules.
    3.   ?    The bond angle is 180°.
    4.   ?    The oxygen atom has one lone pair of electrons.

18. Which one of the following has the largest electronegativity value?
    

    1.   ?    carbon
    2.   ?    hydrogen
    3.   ?    iodine
    4.   ?    oxygen

19. Which one of the following contains a triple bond?
    

    1.   ?    N₂
    2.   ?    CO₂
    3.   ?    BF₃
    4.   ?    C₂H₄