Topic 5 Group 14

Which of the following statements about carbon is not correct?

• All carbon compounds are covalent.

• The most stable oxidation state of carbon is +4.

• Carbon has simple covalent structure.

• Diamond is an allotrope of carbon.

Which of the following statements about Group 14 is true?

• The +4 oxidation state become more stable going down Group 14.

• The melting point increases going down Group 14.

• The boiling points of Group 14 tetrachlorides increases going down the group.

• Conductivity of Group 14 elements decreases going down the group.

Tin(II) chloride decolourises an acidified solution of potassium manganate(VII). Which of the following statements best explained about this reaction.

• Tin(II) chloride is a powerful oxidising agent.

• Tin(II) is unstable.

• Tin(II) is more stable than Tin(IV)

• Potassium manganate(VII) is a powerful oxidising agent.

In diamond, each carbon atom has connected to how many carbon atoms?

• 4

• 3

• 6

• 8

Why PbCl₄ forms greenish yellow fumes when heated but CCl₄ does not form any fumes?

• Carbon is less stable with +4 oxidation state.

• PbCl₄ is very reactive

• Colourless fumes produced by CCl₄ is difficult to be observed.

• Pb is more stable in +2 oxidation state.

Silicon(IV) oxide

• is an ionic compound with strong electrostatic force

• has weak van der Waals forces between molecules

• has giant layered structure

• has high lattice energy

Diamond is a non-conductor because

• diamond has no valence electrons

• diamond is very hard

• diamond does not have delocalised electrons

• diamond has tetrahedral shape

State the similarity between graphite and diamond?

• They have giant molecular structure

• Valence electrons are delocalised

• The atoms are bonded in tetrahedral shape

• Both can conduct electricity

Boiling point of

• Sn is higher than Pb

• C is lower than Ge

• Pb is higher than Si

• C is highest, followed by Si, Ge, Pb and Sn

The following properties is the reason for the use of diamond in high speed drilling materials except for

• diamond is hard

• diamond has giant covalent structure

• diamond has layered structure with van der Waals forces

• diamond has strong covalent bonds