Covalent Structures

• What are giant covalent structures made of?

  Atoms bonded by strong covalent bonds
• Why do giant covalent structures have high melting and boiling points?

  Lots of energy is needed to overcome bonds
• Do giant covalent structures conduct electricity?

  They generally do not conduct electricity
• What is an exception to the conductivity of giant covalent structures?

  Some can conduct electricity, like graphite
• Name three examples of giant covalent structures.

  Diamond, graphite, silicon dioxide
• What are giant covalent structures useful for?

  They are useful in electronics and composites
• What are alloys?

  Mixtures of metals
• How do the properties of alloys differ from pure metals?

  Alloys have slightly different properties
• What are some properties of alloys compared to pure metals?

  Alloys have lower melting points and are harder
• What is the bonding structure of diamond?

  Carbon atoms form four covalent bonds
• How does the bonding in graphite differ from that in diamond?

  Graphite has no covalent bonds between layers
• What is the hardness and melting point of diamond?

  Diamond is very hard and has a high melting point
• What is the texture and conductivity of graphite?

  Graphite is soft, slippery, and conducts electricity
• What type of electrons allow graphite to conduct electricity?

  Delocalised electrons
• How many covalent bonds does each carbon atom form in graphite?

  Three covalent bonds
• What is Buckminsterfullerene (C60)?

  A spherical molecule of carbon
• What was significant about Buckminsterfullerene (C60)?

  It was the first fullerene discovered