Which group contains elements composed of diatomic molecules at stp
The Correct Answer and Explanation is:
The group that contains elements composed of diatomic molecules at standard temperature and pressure (STP) is Group 17, also known as the halogens. This group includes elements like fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
At STP, fluorine, chlorine, bromine, and iodine naturally exist as diatomic molecules (F₂, Cl₂, Br₂, I₂). This means that they are composed of two atoms of the same element bonded together. Astatine, however, is a very rare and radioactive element, and its molecular form at STP is not well-studied due to its scarcity.
The halogens are highly reactive nonmetals, and their tendency to form diatomic molecules arises from their need to complete their valence electron shell. Each halogen has seven valence electrons, and by forming a diatomic molecule, each atom shares one electron with another atom, thus achieving a stable electron configuration similar to that of noble gases.
The diatomic nature of these molecules can be explained by the covalent bonding between the atoms. The sharing of electrons allows the atoms to attain a full outer electron shell, following the octet rule, which is particularly stable for nonmetals.
The diatomic molecules of halogens have distinct properties at STP. Fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid. All of these elements have strong electronegativity, which means they attract electrons very strongly in chemical reactions, contributing to their high reactivity.
The diatomic nature of these elements is also seen in other groups, like the noble gases under certain conditions, but the halogens are the most well-known and consistent group exhibiting this molecular form at STP.
