Covalent Bonding Notes
- Atoms that share electrons form covalent bonds. These atoms 'fill' their outer shells with shared electrons.
- Common covalent compounds are H2O, O2, glucose (C6H12O6).
- 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.
- 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.
- Usually we don't use Lewis Diagrams to show covalent bonding:
- Structural formulas are used instead. Each bond line represents a pair of shared electrons:
H | O H - C - H / \ | H H H
- Elements that form covalent bonds have:
- high ionization energies (don't lose electrons easily).
- high electron affinities (attract electrons readily).
- Covalent bonded compounds are:
- don't conduct electricity.
- have low melting points.