Final answer:
Elements such as hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine exclusively exist as diatomic molecules, each composed of two atoms bonded together to achieve stability.
Step-by-step explanation:
The group that contains only elements which normally exist as diatomic molecules includes hydrogen (H₂), nitrogen (N₂), oxygen (O₂), fluorine (F₂), chlorine (Cl₂), bromine (Br₂), and iodine (I₂). These elements naturally pair up to form molecules consisting of two atoms each due to their chemical properties. For instance, oxygen (O₂) forms a diatomic molecule as it has six valence electrons and forms a double bond to achieve a stable octet configuration in each atom. Similarly, halogens like fluorine, chlorine, bromine, and iodine form diatomic molecules as they all have seven valence electrons and bond with another atom of their kind to complete their valence shell.