This question is about the properties of elements in Groups 1, 7, and 0.
Sodium is a Group 1 alkali metal.
A teacher adds a small piece of sodium to a trough of water. The sodium fizzes and moves rapidly across the surface of the water.
Describe two other observations you would make.
Reactivity decreases going down Group 7 from fluorine to iodine.
Explain this trend in reactivity.
Use ideas about the electronic configurations of the atoms in your answer.
Look at the table. It shows information about some Group 7 elements.
Complete the gaps (i), (ii), and (iii) in the table.
| Element | Formula | Colour | State at room temperature |
|---|---|---|---|
| Fluorine | F2\text{F}_2F2 | (i) ...................... | gas |
| Chlorine | (ii) ...................... | pale green | gas |
| Bromine | Br2\text{Br}_2Br2 | red-brown | (iii) ...................... |
| Iodine | I2\text{I}_2I2 | grey-black | solid |
Chlorine boils at −34 ∘C-34\text{ }^\circ\text{C}−34 ∘C.
Explain why chlorine has a low boiling point.
Helium and neon are elements in Group 0 (the noble gases) and are extremely unreactive.
Explain why, in terms of their electronic configurations.
41 exam-style questions on OCR GCSE Chemistry Predicting chemical reactions. Each one has a worked solution and a mark scheme showing where the marks go.