Links for Chapter 4: Structure
Video clips and animations
- The structure of sodium chloride
Short animation of the structure of a sodium chloride crystal, showing how the coming together of the ions leads to the model of the crystal we normally use. YouTube.
- Animation of sodium chloride dissolving in water - 1.
Short animation showing how water molecules break up a crystal of sodium chloride. YouTube
- Animation of sodium chloride dissolving in water - 2.
Short Flash animation showing how water molecules break up a crystal of sodium chloride. The essential difference between this and the previous one relates to the number of water molecules attaching to each kind of ion. The water molecules don't bind very permanently to the sodium ions, and typically a sodium ion will have 3 - 4 water molecules closely attached. Neither animation shows that. This second animation is more accurate with regard to the number of waters around the chloride ion, though. This level of detail doesn't particularly matter at this level. Provided you understand how a crystal is pulled apart by water molecules, that is all you really need.
- Useful overview
A good text plus animations summary of states of matter, atoms and molecules, mixtures and compounds, plus a useful introduction to formulae for the next chapter. The only criticisms are that the molecules in the liquid are too far apart, and it isn't entirely obvious what is wanted in the very last animation.
Other interesting sites
- Intermolecular forces
An introduction to intermolecular forces from the main part of Chemguide. Aimed at A level, but accessible to GCSE students who might be interested.
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© Jim Clark 2009