chapter 8 - molecules in the gas phase

  • coordinate covalent bond/dative bond: covalent bond formed when both electrons in the bond come from the same atom

    • NH₄⁺, H₃O⁺,

  • electronegativity:

    • tendency to attract more bonded electrons

    • increases as you go rightwards on the periodic table & decreases as you go down on the periodic table

  • pi bond:

    • a bond formed by the overlap of orbitals in a side-by-side fashion with the electron density concentrated above and below the plane of the nuclei of the bonding atoms

      • eg pz-pz in O₂

      • responsible for double bonding

  • sigma bond:

    • a bond formed by the overlap of orbitals in a head-to-head fashion

    • pretty much every single covalent bond is a sigma bond

      • in ethene the C-C bond is one sigma bond (sp²-sp²) and the other is a pi bond

  • sigma bond strong, pi bond weak

  • each double bond is 1 sigma bond & 1 pi bond

  • isomers: compounds with the same molecular formula but different structures

  • when doing the orbital representation of compounds, make sure to count the number of bonds and lone pairs to see how you should distribute electrons!!!

  • Be forms covalent bonds

  • covalent bond with ionic character = polar bond