which element exists as a diatomic molecule at STP
The Correct Answer and Explanation is:
At standard temperature and pressure (STP), several elements exist as diatomic molecules. These elements include hydrogen (H₂), nitrogen (N₂), oxygen (O₂), fluorine (F₂), chlorine (Cl₂), bromine (Br₂), and iodine (I₂). The reason these elements exist in diatomic form at STP is due to their molecular structure and the tendency to form stable bonds with themselves, achieving a more stable electron configuration.
The halogens, which are found in Group 17 of the periodic table, commonly form diatomic molecules because they each have seven valence electrons. By bonding with another atom of the same element, they can fill their valence shell with eight electrons, following the octet rule. For example, chlorine (Cl) shares one electron with another chlorine atom, resulting in a Cl₂ molecule. This bond is held together by a covalent bond, where the atoms share electrons to stabilize their outer shells.
Nitrogen (N₂) and oxygen (O₂) are also diatomic at STP, but their bonding is slightly different. Nitrogen molecules (N₂) are held together by a very strong triple bond, which makes the N₂ molecule quite stable. Oxygen molecules (O₂) are held together by a double bond, which is strong but not as much as the nitrogen triple bond.
Hydrogen (H₂) is another diatomic molecule that forms because each hydrogen atom has one electron and needs one more to achieve a stable configuration. By sharing their electrons, two hydrogen atoms form a single covalent bond.
These diatomic molecules are more stable at STP than their individual atoms due to the energy released when the bonds form. Therefore, elements like H₂, O₂, N₂, F₂, Cl₂, Br₂, and I₂ are commonly found as diatomic molecules in nature at STP.
