11 Asa Chemistry Chemicalbonding Lessonplan

Instructional Objectives

  • Describe ionic (electrovalent) bonding, as in sodium chloride and magnesium oxide, including the use of ‘dot-and-cross’ diagrams
  • Describe, including the use of ‘dot-and-cross’ diagrams,
    • Covalent bonding, as in hydrogen, oxygen, chlorine, hydrogen chloride, carbon dioxide, methane, ethene
    • Co-ordinate (dative covalent) bonding, as in the formation of the ammonium ion and in the Al2Cl6molecule
  • Explain the shapes of, and bond angles in, molecules by using the qualitative model of electron-pair repulsion (including lone pairs), using as simple examples: BF3(trigonal), CO2(linear), CH4(tetrahedral), NH3(pyramidal), H2O (non-linear), SF6 (octahedral), PF5 (trigonal bipyramid))
  • Describe covalent bonding in terms of orbital overlap, giving σ and πbonds, including the concept of hybridisation to form sp, sp2 and sp3 orbitals
  • Explain the shape of, and bond angles in, the ethane, ethene and benzene molecules in terms of σ and π bonds
  • Predict the shapes of, and bond angles in, molecules analogous to those specified in 3rd and 5th point
  • Describe hydrogen bonding, using ammonia and water as simple examples of molecules containing N-H and O-H groups
  • Understand, in simple terms, the concept of electronegativity and apply it to explain the properties of molecules such as bond polarity, the dipole moments of molecules, the behaviour of oxides with water and the acidities of chlorine-substituted ethanoic acids
  • Explain the terms bond energy, bond lengthand bond polarityand use them to compare the reactivities of covalent bonds
  • Describe intermolecular forces (van der Waals’ forces), based on permanent and induced dipoles, as in CHCl3 , Br2 and the liquid noble gases
  • Describe metallic bonding in terms of a lattice of positive ions surrounded by mobile electrons
  • Describe, interpret and/or predict the effect of different types of bonding (ionic bonding, covalent bonding, hydrogen bonding, other intermolecular interactions, metallic bonding) on the physical properties of substances
  • Deduce the type of bonding present from given information
  • Show understanding of chemical reactions in terms of energy transfers associated with the breaking and making of chemical bonds

Teaching Process

  • A quick recap on the already taught concepts of ionic and covalent bonding
  • Check up questions in class for practice
  • Classroom teaching should suffice for the rest of the topics

Suggested reading

Activites

  • Experiments with titration are continued
  • Hands on modeling with molecular modeling kit.

Evaluation

  • End of chapter questions
  • Extended questions (If needed)
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