The molecular nitrogen is not reactive due to: (a) Small internuclear distance of \(\mathrm{N}\) -atom (b) Triple bond in \(\mathrm{N}\) -atom (c) Double bond in \(\mathrm{N}\) -atom (d) High electronegativity of \(\mathrm{N}\)

Chemical bonds are the fundamental forces that hold atoms together in molecules. They can be broadly classified into three types: ionic, covalent, and metallic bonds.

In an ionic bond, one atom donates an electron to another, creating a pair of ions with opposite charges that attract each other. Metallic bonds involve a sea of electrons shared among a lattice of metal ions. Covalent bonds, however, are the type of bond that concerns us with molecular nitrogen, as they involve the sharing of electron pairs between atoms.

The strength and number of these covalent bonds determine the energy required to break them, thus affecting the molecule's reactivity. When we consider molecular nitrogen (\(N_2\)), we're dealing with the kind of covalent bond known as a triple bond, which is particularly strong.

Triple bonds, as found in molecular nitrogen, consist of six shared electrons - three pairs in total. This type of bond is characterized by its bond order (the number of shared electron pairs), which in this case is three, higher than that of a single bond (one pair) or a double bond (two pairs).

The presence of a triple bond means that atoms are held together very tightly due to the strong overlap of atomic orbitals, creating a shorter and stronger bond. This strong triple bond in molecular nitrogen is not only one of the strongest covalent bonds but also results in a molecule with a small internuclear distance. This compactness and strength contribute significantly to the molecule's low reactivity because more energy is required to break these bonds compared to single or double bonds.

Molecular stability is influenced by various factors, including the strength of its chemical bonds and the molecule's electron configuration. In general, a molecule with strong bonds and a complete electron configuration will be more stable and less reactive.

For molecular nitrogen (\(N_2\)), the triple bond means that both nitrogen atoms achieve a stable electronic configuration similar to inert gases, explaining why it's considerably less reactive than many other molecules. In contrast to other elements like oxygen, which also has high electronegativity but forms double bonds (\(O=O\) in molecular oxygen), the triple bond in nitrogen results in a significantly higher degree of stability. Therefore, it requires extreme conditions, such as high temperatures or the presence of a catalyst, to initiate a reaction involving molecular nitrogen.