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Why do halogen elements readily gain electrons in chemical reactions?
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halogen
Modern version of the periodic table of the elements.
Halogen elements readily gain electrons in chemical reactions because of their specific electronic structure. Each halogen atom possesses seven valence electrons in its outermost electron shell.12
By acquiring one additional electron, a halogen atom achieves a full outer shell, resulting in an electron configuration identical to that of the noble gas immediately following it in the periodic table. These configurations are exceptionally stable. Because they can reach this stable state by receiving an electron from another atom, halogens are highly reactive and act as strong oxidizing agents. This tendency is further supported by their high electron affinity, which is the energy released when an atom gains an electron.123