No, oxygen does not always form covalent bonds. While oxygen is known to commonly participate in covalent bonding, it can also form other types of bonds depending on the circumstances.
In a covalent bond, atoms share electrons to complete their outer electron shells. Oxygen typically forms covalent bonds when it reacts with other nonmetallic elements or compounds, such as in the formation of water (H2O) or carbon dioxide (CO2). In these cases, oxygen shares electrons with other atoms to achieve a stable electron configuration.
However, oxygen can also form other types of bonds. For example, oxygen can form ionic bonds when it reacts with metallic elements. In an ionic bond, electrons are transferred from one atom to another, resulting in the formation of charged particles called ions. Oxygen can gain two electrons to become an oxide ion (O2-) when it reacts with metals like sodium (Na), forming sodium oxide (Na2O).
Furthermore, oxygen can participate in metallic bonding in certain situations. Metallic bonding occurs in metals, where the outer electrons of metal atoms are delocalized and form a "sea" of electrons that can move freely throughout the material. Oxygen is not typically a metallic element, but it can be alloyed with metals to form metal oxides, where oxygen participates in the metallic bonding within the structure.
In summary, while oxygen commonly forms covalent bonds, it can also form ionic bonds and participate in metallic bonding depending on the elements and compounds it interacts with. The specific type of bond formed by oxygen depends on the nature of the other atoms or ions involved in the chemical reaction.