Complete the following sentence with either increases or decreases.The reactivity of Group 1 elements ………….. as you go down the group.

The reactivity of Group 1 elements increases as you go down the group.

This trend can be explained by considering the atomic structure and the nature of Group 1 elements, which are alkali metals (such as lithium, sodium, potassium, etc.). As we move down the group from lithium to cesium, the atomic number increases, leading to an increase in the number of electron shells. Consequently, the outermost electron, which is responsible for the reactivity of these metals, is located further from the nucleus.

The greater distance from the nucleus weakens the attractive force between the positively charged protons in the nucleus and the negatively charged outer electron. As a result, it becomes easier for these elements to lose their outer electron, thereby increasing their reactivity. This is why cesium is more reactive than lithium, demonstrating that the reactivity of Group 1 elements indeed increases down the group.