Question

What are binary molecular compounds made of?

Answer 1

Hint: Inorganic compounds include a wide variety of compounds and they are broadly classified into two classes – ionic compounds and molecular compounds. The two differ in the type of bonding between atoms. And the compounds that are formed due to the interaction between two elements are known as binary compounds.

Complete answer:
Each element possesses a specific set of characteristic properties and their interaction with other elements can be studied on the basis of these properties. One of the characteristic properties that play a major role in bonding is electronegativity.
If reacting elements include a highly electronegative element and an electropositive element, then the resulting bond will be ionic in nature. Because the highly electronegative element would accept an electron to complete its octet and the electropositive element would easily lose an electron to attain a stable octet configuration. Transfer of electrons will result in ions that are held together by the electrostatic force of attractions. Such bonding occurs between a metal and a non-metal.
When the reacting elements do not differ much in electronegativity, then they tend to share electrons among themselves. This sharing of electrons results in the formation of a covalent bond. And the compound formed is known as the covalent or molecular compound.
Usually, covalent bonds form between a metal and a nonmetal. Thus, the binary molecular compounds are the compounds formed due to the covalent interaction between two nonmetals. Examples include nitrogen monoxide $\left( \text{NO} \right)$ , carbon dioxide $\left( \text{C}{{\text{O}}_{2}} \right)$ , etc.

Note:
Sometimes covalent compounds are not completely covalent in nature. It means that electrons are not equally shared in all covalent compounds. The atom with a slightly higher electronegativity value attracts electrons more strongly towards itself and this results in accommodation of partially negative charge on that atom and partial positive charge on others. Such compounds are said to be polar.