Astatine ($\mathrm{At}$) lies below iodine at the bottom of Group $17$. Discuss with a partner, and then predict astatine's colour.

Chlorine water is mixed with a solution of potassium iodide in a test tube, $2 {\mathrm{cm}}^3$ of cyclohexane is added to the test tube, which is stoppered and shaken, then allowed to stand.

a. Write a balanced symbol equation, including state symbols, for the reaction that occurs.
b. Write an ionic equation for this reaction.
c. What color is the cyclohexane layer at the end of the experiment?

Astatine ($\mathrm{At}$) lies below iodine at the bottom of Group $17$. Discuss and predict the equation for its reaction with hydrogen.

Astatine ($\mathrm{At}$) lies below iodine at the bottom of Group $17$. Discuss and predict the vigour of its reaction with hydrogen.

Astatine ($\mathrm{At}$) lies below iodine at the bottom of Group $17$. Discuss and predict the thermal stability of its hydride.