Predicting the properties of francium
3 marks · EasyTable 1 shows the melting points of some alkali metals.
| Element | Melting point / °C |
|---|---|
| Lithium | 180.5 |
| Sodium | 97.8 |
| Potassium | 63.5 |
| Rubidium | 39.3 |
| Caesium | 28.5 |
Describe the trend in melting points as you go down Group 1.
Use the trend to estimate the melting point of francium.
Francium's predicted melting point is below room temperature in a warm country. What state (solid, liquid or gas) might it be in during a hot day?
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) Melting point decreases down the group.
(b) Around 22°C (accept 21–27°C) °C
(c) Liquid
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States melting point decreases down Group 1.
B1 (b) · 1 mark · Estimates francium's melting point as about 22°C (accept 21–27°C).
B1 (c) · 1 mark · States francium might be a liquid if the temperature is above its melting point.
Worked solution
a) Melting point decreases as you go down Group 1.
b) Francium's melting point is predicted to be about 22°C.
c) On a hot day with a temperature above 22°C, francium could be a liquid.