Simplify the following text for a Grade 14 native English-speaking person.
Original: Compared with other alkali metals , sodium is generally less reactive than potassium and more reactive than lithium , in accordance with `` periodic law '' : for example , their reaction in water , chlorine gas , etc.
Simplified: Compared with other alkali metals ( metals in the first column of the periodic table ) , sodium is usually less reactive than potassium and more reactive than lithium .