Covalent Bonding Notes

• Atoms that share electrons form covalent bonds. These atoms 'fill' their outer shells with shared electrons.
• Elements that form covalent bonds have:
  • high ionization energies (don't lose electrons easily).
  • high electron affinities (attract electrons readily).
• Covalent bonded compounds are:
  • brittle.
  • don't conduct electricity.
  • have low melting points.
• Common covalent compounds are H₂O,    O₂,     glucose (C₆H₁₂O₆).
• Diatomic molecules form when two identical atoms combine with covalent bonds. Examples: O₂, N₂, H₂
• Polar molecules are covalent compounds whose molecules have a positive charge at one end and a negative charge at the other. Water (H₂O) is a polar molecule.
• The bond order is the number of e^- pairs shared between two atoms.
• A single bond shares one e^- pair (two e^-'s). The bond between H and O in H₂O is a single bond.
• A double bond shares two e^- pairs.
• A triple bond shares three e^- pairs. N₂ is a triple bond.
• The more shared e^- (higher bond order) the harder it is to break apart the bond.