5. Fluorine, chlorine, bromine and iodine are elements in group 7 of the periodic table - Edexcel - GCSE Chemistry - Question 5 - 2021 - Paper 1

One other element that is in Group 7 is astatine.

The element that is liquid at room temperature and pressure is C. bromine.

The element that is dark-grey in colour at room temperature and pressure is D. iodine.

To calculate the empirical formula:

1. Convert grams to moles:

   • Moles of tin (Sn):

   $\text{moles of Sn} = \frac{1.199\text{ g}}{119.0\text{ g/mol}} \approx 0.01008 \text{ moles}$

   • Moles of chlorine (Cl):

   $\text{moles of Cl} = \frac{1.429\text{ g}}{35.5\text{ g/mol}} \approx 0.04024 \text{ moles}$

2. Find the smallest mole ratio:

   • Divide both by the smallest number of moles:

   $\text{ratio of Sn} = \frac{0.01008}{0.01008} = 1$ $\text{ratio of Cl} = \frac{0.04024}{0.01008} \approx 4$

3. Empirical formula: Based on the ratio, the empirical formula is SnCl₄.