Alkali metal
= Alkali metal
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An <alkali metal> is a group-1 metallic element, such as lithium, sodium, or potassium; hydrogen is in group 1 but is not ordinarily classified as an alkali metal. These metals commonly form singly charged positive ions.
Their outer-electron configuration helps explain related chemical behavior across the group. Physical properties and detailed reactivity still vary, so group membership is an organizing pattern rather than identity of all properties.