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Figure 4 shows information about some of the elements in group 7 of the periodic table - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2016 - Paper 1
Question 4
Figure 4 shows information about some of the elements in group 7 of the periodic table. element melting point / °C boiling point / °C fluorine -220 ... show full transcript
Worked Solution & Example Answer:Figure 4 shows information about some of the elements in group 7 of the periodic table - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2016 - Paper 1
Step 1
Estimate the boiling point of astatine.
Answer
To estimate the boiling point of astatine, we first observe the trend in the boiling points of the preceding elements in group 7. The boiling point increase can be noted as follows:
- Chlorine: -35 °C
- Bromine: 59 °C
- Iodine: 184 °C
From these values, it is evident that the boiling point increases as we move down the group. The difference between the boiling points of chlorine and bromine is 94 °C, and from bromine to iodine, it is 125 °C. Taking this trend into account, we can infer that the boiling point of astatine would be higher than that of iodine.
By extrapolating the trend, a reasonable estimate for the boiling point of astatine would be around 220 °C.
Step 2