Alkali Metals & Alkaline Earth Metals

Groups 1 and 2 of the periodic table contain some of the most reactive metals known. These elements demonstrate clear periodic trends and provide an excellent introduction to how position in the table dictates chemical behaviour.

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Hydrogen — The Exception

Before discussing Group 1, it is important to note that hydrogen (H, atomic number 1) sits at the top of Group 1 but is not an alkali metal. Hydrogen is a non-metal gas under standard conditions. It is placed in Group 1 because it has one valence electron, but its chemistry is unique — it can both lose and gain an electron, behaving as a metal in some reactions and a non-metal in others.

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Group 1: The Alkali Metals