(g) Covalent bonding |
1.44 know that a covalent bond is formed between atoms by the sharing of a pair of electrons |
1.45 understand covalent bonds in terms of electrostatic attractions |
1.46 understand how to use dot-and-cross diagrams to represent covalent bonds in:
- diatomic molecules, including hydrogen, oxygen, nitrogen, halogens and hydrogen halides
- inorganic molecules including water, ammonia and carbon dioxide
- organic molecules containing up to two carbon atoms, including methane, ethane, ethene and those containing halogen atoms
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1.47 explain why substances with a simple molecular structures are gases or liquids, or solids with low melting and boiling point – the term intermolecular forces of attraction can be used to represent all forces between molecules |
1.48 explain why the melting and boiling points of substances with simple molecular structures increase, in general, with increasing relative molecular mass |
1.49 explain why substances with giant covalent structures are solids with high melting and boiling points |
1.50 explain how the structures of diamond, graphite and C60 fullerene influence their physical properties, including electrical conductivity and hardness |
1.51 know that covalent compounds do not usually conduct electricity |