No, the strong nuclear force is not responsible for holding atoms together to form a molecule or molecules together to form a substance. The strong nuclear force is one of the fundamental forces in nature, and its primary role is to bind protons and neutrons together within an atomic nucleus. It is responsible for the stability and structure of atomic nuclei.
The force that holds atoms together to form a molecule is known as the chemical bond. Chemical bonds are formed when atoms share or transfer electrons. There are several types of chemical bonds, including covalent bonds, ionic bonds, and metallic bonds, depending on the nature of electron sharing or transfer.
Once molecules are formed, the attractive forces between molecules are responsible for holding them together to form a substance. These forces are collectively known as intermolecular forces. The specific intermolecular forces involved depend on the types of molecules and the conditions of the substance. Some common types of intermolecular forces include van der Waals forces, dipole-dipole interactions, and hydrogen bonding. These forces determine the physical properties of substances, such as melting point, boiling point, and solubility.