How do halogens achieve the electron configuration of a noble gas?

Halogen atoms achieve the electron configuration of a noble gas by acquiring one additional electron to complete their outermost electron shell.1

Each halogen atom possesses seven valence electrons in its outermost shell, arranged in s and p orbitals. Because these elements are located in Group 17 of the periodic table—immediately preceding the noble gases—they have a strong tendency to gain a single electron from another atom. By filling this vacancy, the halogen atom attains the same stable electron configuration as the noble gas that follows it in the periodic table.12

This process results in the formation of a stable anion, which is a key factor in the high electron affinity and strong oxidizing properties characteristic of the halogens.134