CAIE A Level Chemistry 9701 · The Periodic Table: chemical periodicity
The table shows the atomic radii of the Period 3 elements Na to Ar.
| Element | Na | Mg | Al | Si | P | S | Cl | Ar |
|---|---|---|---|---|---|---|---|---|
| Atomic radius / nm | 0.186 | 0.160 | 0.143 | 0.117 | 0.110 | 0.104 | 0.099 | 0.098 |
Describe and explain the general trend in atomic radius across Period 3.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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