MediumChemistryHigh School (9–10)GeneralThe Periodic Table › Groups and FamiliesNumerical

The melting points of lithium and potassium are 454 K and 337 K.

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The melting points of lithium and potassium are $454\ \text{K}$ and $337\ \text{K}$ . Estimate the melting point of sodium, which is between them. The real value is $371\ \text{K}$ . What is the error, as a percentage of the real value?

Need a reminder? The key ideaShow

The position predicts the valency, the formulas, the reactivity and the nature of an element. A property in the middle of a group can be estimated as the average of its two neighbours, but only roughly.

The worked solution

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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.

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