Covalent Bonding

• What do atoms form by sharing electrons?

  Covalent bonds
• Why do atoms transfer electrons in ionic bonds?

  To achieve a full outer shell
• What happens when two non-metal elements need extra electrons?

  They share electrons instead of transferring
• What is the name of the diagram used to represent shared electrons?

  Dot and cross diagram
• How do you differentiate electrons in a dot and cross diagram?

  Use dots for one atom and crosses for another
• What is a simpler way to draw covalent molecules?

  Displayed formula
• What is a disadvantage of displayed formulas?

  They don't show the 3D shape of molecules
• What is the molecular formula for ammonia?

  NH₃
• How many hydrogen atoms are in ammonia?

  Three hydrogen atoms
• How does nitrogen achieve a full outer shell in ammonia?

  By sharing electrons with three hydrogen atoms
• What do you do to create a displayed formula from a dot and cross diagram?

  Remove shells and replace shared electrons with lines
• What is a key feature of 3D models of molecules?

  They show the arrangement of atoms in space
• What are simple molecular substances?

  Small molecules with strong covalent bonds
• What type of forces exist between individual molecules in simple molecular substances?

  Weak intermolecular forces
• What is the chemical formula for water?

  H₂O
• What is the chemical formula for methane?

  CH₄
• What are polymers made of?

  Repeating units called monomers
• What are giant covalent structures?

  Large structures with billions of atoms
• What is the arrangement of atoms in giant covalent structures?

  Regular lattice formation
• What type of bonds hold atoms together in giant covalent structures?

  Covalent bonds
• Why are giant covalent structures strong?

  All atoms are joined by covalent bonds
• How do covalent bonds differ in simple molecular substances and giant covalent structures?

  Simple substances have weak forces; giants have strong bonds
• What are the different ways to represent covalent bonds?

  • Dot and cross diagrams
  • Displayed formulas
  • 3D models
• What are the characteristics of simple molecular substances?

  • Small molecules
  • Strong covalent bonds within molecules
  • Weak intermolecular forces between molecules
• What are the characteristics of giant covalent structures?

  • Large structures
  • Billions of atoms
  • Strong covalent bonds throughout
  • Regular lattice arrangement