Describe the differences between the reactivity and oxidizing power of Group 7 elements.

The reactivity and oxidizing power of Group 7 elements increase down the group.

Group 7 elements, also known as halogens, are highly reactive non-metals that readily form diatomic molecules. Their reactivity increases down the group due to the increasing atomic radius and decreasing electronegativity. This means that the outermost electron is further from the nucleus and experiences less attraction, making it easier to gain an electron and form a negative ion. For example, fluorine is the most reactive halogen and readily reacts with almost all other elements, while iodine is less reactive and only reacts with certain elements under specific conditions.

The oxidizing power of Group 7 elements also increases down the group. This is because they have a high electron affinity, meaning they readily accept electrons to form negative ions. This makes them good oxidizing agents, as they can oxidize other substances by accepting electrons from them. For example, chlorine is a strong oxidizing agent and can oxidize metals such as iron and copper, while iodine is a weaker oxidizing agent and only reacts with certain substances under specific conditions.

Overall, the reactivity and oxidizing power of Group 7 elements increase down the group due to the increasing atomic radius and decreasing electronegativity, making it easier for them to gain electrons and form negative ions. This makes them highly reactive and good oxidizing agents, with fluorine being the most reactive and chlorine being the strongest oxidizing agent.