Changes

*[[Group 2]]: The [[Alkali Earth Metal]]s all react strongly with steam and acids. The [[reactivity]] increases as you go down the [[group]].

*[[Group 7]]: The [[Halogen]]s all act as bleaching agents and kill bacteria. The reactivity decreases as you go down the [[group]].

: The [[Physical Property|physical properties]] of [[element]]s within a [[group]] are similar. However, the property changes gradually as you move down the [[group]].