Ionic bonding
(a) ionic bonding as electrostatic attraction between positive and negative ions, and the construction of 'dot-and-cross' diagrams
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(b) explanation of the solid structures of giant ionic lattices, resulting from oppositely charged ions strongly attracted in all directions e.g. NaCl
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(c) explanation of the effect of structure and bonding on the physical properties of ionic compounds, including melting and boiling points, solubility and electrical conductivity in solid, liquid and aqueous states
Covalent bonding
(d) covalent bond as the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
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(e) construction of ‘dot-and-cross’ diagrams of molecules and ions to describe:
(i) single covalent bonding
(ii) multiple covalent bonding
(i) dative covalent (coordinate) bonding
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(f) use of the term average bond enthalpy as a measurement of covalent bond strength
The shapes of simple molecules and ions
(g) the shapes of, and bond angles in, molecules and ions with up to six electron pairs (including lone pairs) surrounding the central atom as predicted by electron pair repulsion, including the relative repulsive strengths of bonded pairs and lone pairs of electrons
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(h) electron pair repulsion to explain the following shapes of molecules and ions: linear, non-linear, trigonal planar, pyramidal, tetrahedral and octahedral
Electronegativity and bond polarity
(i) electronegativity as the ability of an atom to attract the bonding electrons in a covalent bond; interpretation of Pauling electronegativity values
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(j) explanation of:
(i) a polar bond and permanent dipole within molecules containing covalently-bonded atoms with different electronegativities
(ii) a polar molecule and overall dipole in terms of permanent dipole(s) and molecular shape
Intermolecular forces
(k) intermolecular forces based on permanent dipole–dipole interactions and induced dipole– dipole interactions
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(l) hydrogen bonding as intermolecular bonding between molecules containing N, O or F and the H atom of –NH, –OH or HF
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(m) explanation of anomalous properties of H2O resulting from hydrogen bonding, e.g.:
(i) the density of ice compared with water
(ii) its relatively high melting and boiling points
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(n) explanation of the solid structures of simple molecular lattices, as covalently bonded molecules attracted by intermolecular forces, e.g. I 2, ice
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(o) explanation of the effect of structure and bonding on the physical properties of covalent compounds with simple molecular lattice structures including melting and boiling points, solubility and electrical conductivity.