Halogens are elements found in Group 7 of the periodic table. They have some interesting changes in their chemical properties as you go down the group. Let’s break these down:

1. Reactivity: Reactivity is how easily an element can combine with others. As you move from fluorine to iodine, the reactivity goes down. Fluorine is super reactive and easily makes new compounds. On the other hand, iodine is much less reactive and does not form compounds as easily.

2. Oxidizing Power: The ability to gain electrons, or oxidizing power, also decreases when you go down the group. Fluorine is a strong oxidizer, meaning it can take electrons away from other elements very well. But iodine is weaker at this.

3. Displacement Reactions: In these reactions, more reactive halogens can take the place of less reactive ones in compounds. For example, if you let chlorine gas mix with a sodium bromide solution, the chlorine will push the bromine out. This creates sodium chloride and bromine gas.

These patterns happen because the size of the atoms gets bigger and their ability to attract electrons gets weaker as you move down the group.