OHST Practice Exam

Which of the elements listed below belong to the halogen group?

1. Na, Ca, K

2. C, O, H

3. F, Cl, Br, I

4. Au, Ag, Pt

The correct answer is: F, Cl, Br, I

The halogen group, found in Group 17 of the periodic table, consists of five elements—fluorine, chlorine, bromine, iodine, and astatine. The elements in this group are characterized by their high reactivity and tendency to form salts when combined with metals. Fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) are well-known halogens, each exhibiting distinct properties that reflect their position in the periodic table. For example, fluorine is the most reactive, while iodine is less reactive but is still classified as a halogen. This unique reactivity and their ability to form bonds with various elements makes the group significant in both industrial applications and chemical reactions. The alternative options include elements from different groups of the periodic table: the first option mentions alkali and alkaline earth metals, the second option includes nonmetals like carbon, oxygen, and hydrogen, and the last option lists precious metals. None of these groups contain halogens, thereby confirming that the correct answer is indeed the group of fluorine, chlorine, bromine, and iodine.