The melting points of lithium and potassium are 454 K and 337 K.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
The melting points of lithium and potassium are and . Estimate the melting point of sodium, which is between them. The real value is . 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
Have you tried it?
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.
Step 1. Estimate. .
Step 2. Difference. .
Step 3. Error. .
Answer: , off by , because melting points do not fall in equal steps.
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