Diamond&silicone dioxide

• What are the two giant covalent molecules discussed in this video?

  Diamond and silicon dioxide
• What is the structure of giant covalent substances?

  They contain millions of covalent bonds
• How do the properties of giant covalent substances relate to their structure?

  They have high melting and boiling points due to strong covalent bonds
• What type of forces exist between small covalent molecules?

  Weak intermolecular forces
• Why do small covalent substances have low melting and boiling points?

  Because breaking weak intermolecular forces requires little energy
• What is the state of giant covalent substances at room temperature?

  They are always solids
• What is the melting point of diamond?

  Over 3,700 °C
• Why can't diamond conduct electricity?

  Because all outer electrons are involved in covalent bonds
• What elements make up silicon dioxide?

  Silicon and oxygen
• How does the melting point of silicon dioxide compare to that of diamond?

  Both have very high melting points
• What must happen to melt silicon dioxide?

  All covalent bonds must be broken
• What are the key properties of giant covalent substances?

  • Always solids at room temperature
  • High melting and boiling points
  • Composed of millions of strong covalent bonds
• What distinguishes small covalent molecules from giant covalent substances?

  • Small covalent molecules have few covalent bonds
  • They have weak intermolecular forces
  • They typically exist as gases at room temperature