Summary
Group 7 elements, known as halogens, include chlorine, bromine, and iodine, which are diatomic non-metals showing trends in color and density.
- Halogens — elements in Group 7 that are diatomic non-metals. Example: Chlorine, bromine, and iodine.
- Reactivity — decreases as you go down the group. Example: Chlorine is more reactive than bromine and iodine.
- Displacement Reaction — a more reactive halogen can displace a less reactive one from its salt solution. Example: Chlorine can displace bromide and iodide ions.
Exam Tips
Key Definitions to Remember
- Halogens: Group 7 elements that are diatomic non-metals.
- Reactivity: The tendency of a substance to engage in chemical reactions.
Common Confusions
- Thinking that reactivity increases down Group 7.
- Confusing the color trends of halogens with their reactivity trends.
Typical Exam Questions
- What happens to the reactivity of halogens as you move down the group? Reactivity decreases.
- Which halogen can displace iodide ions? Chlorine.
- What is the state of iodine at room temperature? Solid.
What Examiners Usually Test
- Trends in reactivity and physical properties of Group 7 elements.
- Ability to predict outcomes of displacement reactions involving halogens.