1 Nature of chemical bonding
Bonded atoms are chemically stable if they can achieve a noble gas configuration.
This configuration includes eight electrons in the last electronic orbital. Stable electronic configurations are achieved through ionic, covalent, and dative bonding. Once formed, covalent and dative bonds are identical.
BOND MAKING releases energy ("MEXO"). BONG BREAKING requires energy ("BENDO")
Bonds between atoms within a molecule are intra-molecular bonds:
- Ionic - Between Ions
- Covalent -Share an electron pair
- Dative covalent - One atom donates electron pairs into a covalent bond.
Types of Covalent bonds:
Covalent bonds can be σ(Sigma), π(Pi) or δ(Delta)
- 1. Sigma: - Found in Single bonds 2 s-orbitals or s+p-orbital or p+p-orbital or sp3 + s orbital or sp3 + sp3 orbital
2 s-orbitals or s+p-orbital or p+p-orbital
- 2. Pi: Found in double bonds: Sharing of 2 p-orbitals. Overlap of p orbitals = sideways overlap. Pi bonds are weaker than sigma bonds because the degree of orbital overlap is less and the overlap regions of the orbitals, where there is high, but not max probability to find e-. Found in unsaturated compounds.
Sharing of 2 p-orbitals
- 3. Delta: found in quadruple bonds: 2 d-orbitals or d+f-orbital overlap. Found in ions of complex compounds