How many valence electrons does a halogen atom have?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — halogen Modern version of the periodic table of the elements.

A halogen atom has seven valence electrons in its outermost electron shell.1

These electrons are distributed across two types of orbitals: the s orbital, which holds two electrons, and the p orbital, which holds five. Because they are only one electron short of achieving the exceptionally stable electron configuration of a noble gas, halogens exhibit a strong tendency to acquire an additional electron, which makes them powerful oxidizers.1