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Comparing plum pudding and current models
Figure 2 shows two early models of the atom.
Compare model A with the model of the atom used today. Use Figure 2.
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Marking points
- 1 For full credit, identifies scientifically relevant features and makes clear comparisons between Model A and the current model, noting magnitude where appropriate.
- 2 May credit accurate similarities such as both containing electrons or both being neutral overall.
- 3 May credit accurate contrasts involving the nucleus, particles, charge distribution, electron arrangement, mass distribution, or empty space.
Full-mark answer
Both Model A and the current model contain electrons and are neutral overall. Model A has positive charge and mass spread throughout a solid sphere, with electrons dispersed in it and no nucleus. In the current model, nearly all the mass and all positive charge are concentrated in a tiny central nucleus containing protons and neutrons; electrons occupy shells around it, so most of the atom is empty space.
Why this answer loses marks
The old model has electrons, but the new model has a nucleus.
That gives isolated facts; make clear old-versus-current comparisons for charge, mass or electron arrangement.