Covalent bonding

• Covalent Bonds


  Sharing Electrons
• Covalent bond formation

  1. Non-metal atoms bond together

  2. Share pairs of electrons

  3. Make covalent bonds
• Covalent bonds

  • Electrostatic forces
  • Very strong
• Atoms only share electrons in their outer shells
• Atoms get one extra shared electron for each single covalent bond that they form
• • Each atom usually makes enough covalent bonds to fill up its outer shell
  • This makes them very stable
• Nitrogen


  • Has 5 outer electrons
  • Forms 3 covalent bonds to get the extra 3 electrons it needs for a full outer shell
• Dot and Cross Diagrams

  • Electrons shown in the overlap between two atoms are shared electrons
  • Show which atoms the electrons in a covalent bond come from
  • Don't show how the atoms are arranged or how big the atoms are compared to each other
• Displayed Formulas


  • Show the covalent bonds as single lines between atoms
  • If it's a single covalent bond, there'll be one line
  • If it's a double covalent bond, there'll be two lines
  • Good for showing how atoms are connected in large molecules
  • Don't show the 3D structure of the molecule
  • Don't show which atoms the electrons in the covalent bond have come from
• 3D Models


  • Show the atoms, the covalent bonds and how they're arranged
  • Can be confusing for large molecules
  • Don't show where the electrons in the bonds have come from
• You can find the molecular formula of a simple molecular compound from these diagrams by counting up how many atoms of each element there are