Final answer:
The properties of alkali metals, alkaline earth metals, and halogens are determined by their electron configurations. Alkali metals have one valence electron and are highly reactive. Alkaline earth metals have two valence electrons and are less reactive, while halogens have seven valence electrons and are highly reactive nonmetals.
Step-by-step explanation:
The properties of the alkali metals, alkaline earth metals, and halogens are determined by their electron configurations.
Alkali metals, such as lithium and sodium, have one valence electron and are highly reactive. They readily lose this electron to form stable cations with a charge of 1+.
Alkaline earth metals, like beryllium and magnesium, have two valence electrons. They are less reactive than alkali metals but still form cations with a charge of 2+.
Halogens, such as fluorine and chlorine, have seven valence electrons and are highly reactive nonmetals. They readily gain one electron to achieve a stable electron configuration.