Properties of covalent structure

• What type of bond do non-metals form when they share electrons?

  Covalent bonds
• What is the result of non-metals joining together by covalent bonds?

  They achieve full outer shells of electrons
• What are examples of simple molecular substances?

  Chlorine and ammonia
• What are giant covalent structures made of?

  Huge numbers of non-metal atoms bonded by covalent bonds
• Name three important examples of giant covalent structures.

  Diamond, graphite, and silicon dioxide
• Why do giant covalent structures have high melting and boiling points?

  Because strong covalent bonds need a lot of energy to break
• Why don't simple molecular substances conduct electricity?

  Because there are no free electrons or charged particles
• What is the boiling point of chlorine?

  • 34 degrees Celsius
• How do the boiling points of halogens change as you go down the group?

  The boiling points increase as the molecules get larger
• What is the boiling point of bromine?

  59 degrees Celsius
• What is the boiling point of iodine?

  184 degrees Celsius
• What is the relationship between the size of molecules and intermolecular forces?

  Larger molecules have more intermolecular forces
• What is the structure of giant covalent structures like diamond and graphite?

  They are arranged into regular repeating lattices
• Why does graphite conduct electricity while other giant covalent structures do not?

  Graphite contains free electrons
• What is silicon dioxide also known as?


  Silica
• What is the ratio of silicon to oxygen atoms in silicon dioxide?

  1 to 2
• What is the main component of sand?

  Silicon dioxide
• What are the key differences between simple molecular substances and giant covalent structures?

  • Simple molecular substances:
  • Made of a few atoms
  • Joined by weak intermolecular forces
  • Low melting and boiling points
  • Do not conduct electricity

  
  

  • Giant covalent structures:
  • Made of many atoms
  • Joined by strong covalent bonds
  • High melting and boiling points
  • Generally do not conduct electricity (except graphite)
• What is the significance of intermolecular forces in determining the physical properties of simple molecular substances?

  Intermolecular forces determine the melting and boiling points
• What is the main takeaway regarding the structure of silicon dioxide?

  It is a giant covalent structure made of silicon and oxygen