Diamond and Silicon Dioxide

• What should you be able to describe by the end of this video regarding giant covalent molecules?

  The structure of giant covalent molecules
• What else should you be able to describe about giant covalent molecules by the end of this video?

  The properties of giant covalent molecules
• What should you be able to link to the structure of giant covalent molecules?

  Their properties
• Which giant covalent molecules will be looked at in this video?

  Diamond and silicon dioxide
• What were the molecules looked at in recent videos described as?

  Small covalent molecules
• What property do small covalent molecules have due to their weak intermolecular forces?

  Low melting and boiling points
• What state are giant covalent molecules at room temperature?

  Always solids
• Why are giant covalent molecules solids at room temperature?

  They've got millions of strong covalent bonds
• What property do giant covalent molecules have because they've got millions of strong covalent bonds?

  High melting and boiling points
• What needs to happen to melt giant covalent molecules?

  Break all of these covalent bonds
• Why does melting giant covalent molecules take a great deal of energy?

  Because we have to break all covalent bonds
• What element is diamond formed from?

  Carbon
• How many covalent bonds does each carbon atom form in diamond?

  Four
• How many other carbon atoms does each carbon atom form covalent bonds to in diamond?

  Four
• What does a single diamond contain?

  A huge amount of carbon atoms
• How are the carbon atoms held together in diamond?

  Joined by covalent bonds
• What property does diamond have because it contains a huge amount of carbon atoms joined by covalent bonds?

  A very high melting and boiling point
• What is the melting point of diamond?

  Over 3,700 degrees Celsius
• Why does diamond have a huge number of covalent bonds?

  Each carbon atom forms four strong covalent bonds
• What must be broken when diamond is melted?

  A huge number of covalent bonds
• What does breaking a huge number of covalent bonds in diamond require?

  A great deal of energy
• Why can diamond not conduct electricity?

  Because there are no free electrons
• What is needed to carry electrical charge in a material?

  Free electrons
• What is silicon dioxide commonly called?

  Silica or sand
• What elements does silicon dioxide contain?

  Silicon and oxygen
• How are silicon and oxygen bonded together in silicon dioxide?

  Covalently bonded
• What kind of molecule is silicon dioxide?

  Giant covalent molecule
• What does silicon dioxide contain because it is a giant covalent molecule?

  A huge number of covalent bonds
• What property does silicon dioxide have because of the huge number of strong covalent bonds?

  A very high melting and boiling point
• What takes a great deal of energy in silicon dioxide?

  Breaking the huge number of strong covalent bonds
• Which giant covalent molecule is to be looked at in the next video?

  Graphite