Which elements are categorized as halogens?

Halogens are a specific group of elements located in Group 17 of the periodic table. This group includes Fluorine, Chlorine, Bromine, and Iodine, which are all nonmetals known for their reactivity, particularly in forming salts with metals. They have seven valence electrons and typically gain an electron to achieve a stable noble gas electron configuration.

In contrast, the other groups of elements mentioned do not belong to the halogen category. For example, the first choice lists Oxygen and Nitrogen, which are both in Group 16 and Group 15, respectively, while Fluorine is indeed a halogen but does not make the entire group halogens. The third choice includes Carbon, Boron, Silicon, and Germanium, which are all metalloids or nonmetals found in Group 14 and Group 13. Finally, the last choice consists of Sodium, Potassium, Calcium, and Magnesium, which are alkali and alkaline earth metals from Group 1 and Group 2. Therefore, the only set that contains exclusively halogens is the one with Fluorine, Chlorine, Bromine, and Iodine.