Question

I see that the the standard form of many elements are diatomic molecules under normal conditions (eg oxygen, hydrogen and iodine are usually seen as diatomic molecules) and are all among the most electronegative, and I understand it has to do with energy and stability, but I just have no clue why other elements wouldn't be the same.

What explains why some appear as diatomic molecules and others do not?

Answer 1

Some elements exist as diatomic molecules, such as H₂, O₂, and N₂, because sharing electrons through covalent bonds leads to a full valence shell and increased stability, exemplified by oxygen forming a double bond to achieve an octet.

Step-by-step explanation:

The question addresses why some elements appear as diatomic molecules under normal conditions. Diatomic molecules are two-atom molecules, and this form of existence is especially common among certain elements due to the stability it confers. Elements such as hydrogen (H₂), nitrogen (N₂), oxygen (O₂), and the halogens (fluorine F₂, chlorine Cl₂, bromine Br₂, and iodine I₂) exist as diatomic molecules because they can achieve a full valence shell by sharing electrons through covalent bonds, which makes them more stable than isolated atoms.

For example, in the case of oxygen, each oxygen atom has six valence electrons. By forming a double bond, they share two pairs of electrons, allowing each oxygen atom to reach an octet of valence electrons, thus achieving a stable electron configuration. Related elements, such as sulfur (S₈) and phosphorus (P₄), form molecules with more atoms, again reflecting a stable configuration that maximizes electron sharing and minimizes energy.