Giant Covalent Structures & Allotropes of Carbon

Explain why chlorine is a gas at room temperature.

• It has strong covalent bonds.

• It has weak intermolecular forces.

• It is a metal.

• It has a high boiling point.

From the list below, choose two molecular covalent substances:

• Hydrogen chloride and calcium chloride

• Sodium chloride and aluminium oxide

• Hydrogen chloride and carbon dioxide

• Copper(II) oxide and sodium chloride

What is meant by the term allotropes?

• Different compounds of the same element

• Different forms of the same element in different physical states

• Different forms of the same element in the same physical state

• Different elements with similar properties

Name two allotropes of carbon.

• Diamond and sodium chloride

• Graphite and aluminium oxide

• Diamond and graphite

• Graphene and copper(II) oxide

Describe the structure, bonding and arrangement of atoms in diamond.

• Each carbon atom is bonded to 3 other carbon atoms in layers.

• Each carbon atom is bonded to 4 other carbon atoms in a tetrahedral arrangement.

• Each carbon atom is bonded to 2 other carbon atoms in a linear arrangement.

• Each carbon atom is bonded to 6 other carbon atoms in a hexagonal arrangement.

State one use of graphite.

• Used in solar cells

• Used in cutting tools

• Used as a lubricant

• Used in batteries

Explain why graphene is used in solar cells.

• It is opaque and heavy.

• It is transparent and conducts electricity.

• It is brittle and non-conductive.

• It is reflective and insulates electricity.

Which property of diamond makes it suitable for use in cutting tools?

• It is soft.

• It conducts electricity.

• It is the hardest naturally known substance.

• It has weak bonds.

Why does graphite conduct electricity?

• It has free ions.

• It has delocalised electrons.

• It has a rigid structure.

• It has a high melting point.

What is the arrangement of carbon atoms in graphite?

• Tetrahedral

• Linear

• Layers of hexagons

• Cubic