In this topic,Student should be able to :
a) Characterize electrovalent (ionic) bond as in sodium chloride and calcium oxide.
b) Use the ‘dot-and-cross’ diagrams to explain: i) Covalent bonding, as in hydrogen(H2); oxygen(O2); chlorine(Cl2); hydrogen chloride; carbon dioxide; methane and ethane. ii) Co-ordinate (dative covalent) bonding, as in the formation of the ammonium ion in H3N+– -BF3 and H3O+.
c) Describe the shapes and bond angles in molecules by using the qualitative model of Valence Shell Electron-Pair Repulsion (VSEPR) theory up to 4 pairs of electron including bonded electron pair and lone pair around central atom. d) Describe covalent bonding in terms of orbital overlap, giving and bonds.
e) Explain the shape of and bond angles in ethane, ethene and benzene molecules in terms of and bonds.
f) Describe hydrogen bonding, using ammonia and water as simple examples of molecules containing N-H and O-H groups.
g) Explain the terms bond energy, bond length and bond polarity (electronegativity difference) and use them to compare the nature of covalent bonds i.e. polar and non-polar.
h) Describe intermolecular forces (Van der Waal’s forces), based on permanent and induced dipoles, as in HCl, CHCl3, Halogens and in liquid noble gases.
i) Describe metallic bonding in terms of positive ions surrounded by mobile electrons (sea of electrons).
j) Describe, interpret and/or predict the effect of different types of bonding (ionic bonding; covalent bonding; hydrogen bonding; Van der Waal’s forces and metallic bonding) on the physical properties of substances.
k) Deduce the type of bonding present in a substance from the given information