Covalent Structures

• What type of bond do non-metals form by sharing electrons?

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

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

  • Small molecules formed by non-metals
  • Examples include chlorine and ammonia
  • Atoms are bonded by strong covalent bonds
• What are giant covalent structures?

  • Large networks of non-metal atoms bonded by covalent bonds
  • Examples include diamond, graphite, and silicon dioxide
  • Arranged in regular repeating lattices
• What is a key property of covalent bonds?

  Covalent bonds are very strong
• What must be broken to melt or boil chlorine?

  The weak intermolecular forces between molecules
• At what temperature does chlorine boil?

  • 34 degrees Celsius
• How do intermolecular forces affect the boiling points of halogens?

  Boiling points increase as the size of the molecules increases
• What is the boiling point of bromine?

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

  184 degrees Celsius
• Why don't simple molecular substances conduct electricity?

  They have no free electrons or electric charge
• What are the properties of giant covalent structures?

  • Very strong due to covalent bonds
  • High melting and boiling points
  • Generally do not conduct electricity
• What are the three important examples of giant covalent structures?

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

  Strong covalent bonds must be broken to melt or boil them
• What is an exception to the property of giant covalent structures regarding electrical conductivity?

  Graphite can conduct electricity
• 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 is the key difference between simple molecular substances and giant covalent structures?

  • Simple molecular substances:
  • Small molecules
  • Weak intermolecular forces
  • Giant covalent structures:
  • Large networks of atoms
  • Strong covalent bonds
• What is the structure of silicon dioxide?

  It consists of silicon and oxygen atoms in a repeating lattice