Are ionic and covalent bonds intermolecular forces?
Updated: 2nd October 2019
By textbook, a dipole-dipole interaction is an intermolecular force while a covalent bond, as well as an ionic bond, is a chemical bond. It seems to me that, yes, the forming of ions is a chemical reaction, but the ionic bond is an intermolecular force.
The polar covalent bond is much stronger in strength than the dipole-dipole interaction. The former is termed an intramolecular attraction while the latter is termed an intermolecular attraction. So now we can define the two forces: Intramolecular forces are the forces that hold atoms together within a molecule.
The intermolecular forces in motor oil are therefore London dispersion forces. We generally consider these forces to be weak. Ionic compounds have ionic forces. Covalent compounds all have London dispersion (LD) forces, whereas polar covalent compounds have dipole forces and/or hydrogen-bonding forces.
Intermolecular forces or IMFs are physical forces between molecules. In contrast, intramolecular forces are forces between atoms within a single molecule. There are three major types of intermolecular forces: London dispersion force, dipole-dipole interaction, and ion-dipole interaction.
The four prominent types are:
- Strong ionic attraction. Recall lattice energy and its relations to properties of solid.
- Intermediate dipole-dipole forces.
- Weak London dispersion forces or van der Waal's force These forces alway operate in any substance.
- Hydrogen bond.
- Covalent bonding.
- Metallic bonding.
Intermolecular forces (IMF) are the forces which mediate interaction between molecules, including forces of attraction or repulsion which act between molecules and other types of neighboring particles, e.g., atoms or ions. Ion-induced dipole forces.
The intermolecular forces increase with increasing polarization of bonds. Strength of forces (and therefore impact on boiling points) is ionic > hydrogen bonding > dipole dipole > dispersion. Boiling point increases with molecular weight, and with surface area.
An intramolecular force is any force that binds together the atoms making up a molecule or compound, not to be confused with intermolecular forces, which are the forces present between molecules. Chemical bonds are considered to be intramolecular forces, for example.
intermolecular bonding - hydrogen bonds. This page explains the origin of hydrogen bonding - a relatively strong form of intermolecular attraction. If you are also interested in the weaker intermolecular forces (van der Waals dispersion forces and dipole-dipole interactions), there is a link at the bottom of the page.
The network structure combines to make the substance stronger than normal covalent bonded substances. So to answer your question, substances with standard covalent bonds seem to be weaker than those with ionic bonds because the ionic bonds tend to form a lattice structure, that makes them much stronger.
Viscosity is resistance to flow. For liquids, typically the larger the intermolecular forces (IMF) the higher the viscosity. The other factors that affect viscosity are temperature and the shape of the molecule. Higher temperatures will correspond to higher average kinetic energies and faster moving molecules.
From strongest to weakest, the intermolecular forces rank in the following way:
- Strongest: Hydrogen bonding. This occurs when compounds contain #"O"-"H"# , #"N"-"H"# , or #"F"-"H"# bonds.
- Less strong: Dipole-dipole forces.
- Weakest: London Dispersion Forces.
Intermolecular forces such as dipole-dipole interactions or hydrogen bonding are important to consider when learning about solvation. If the main intermolecular force between molecules is dispersion forces, the molecule is non-polar and will not dissolve well in a polar solvent such as water.
Metallic Bonding & Intermolecular Forces Metallic Bonding Metallic bond is the reaction between molecules within metals called alkali reactive force. The electrons and the positive ions in the metal have a strong attractive force between them. Therefore metals often have high melting or boiling points.
Dipole-Dipole interactions result when two dipolar molecules interact with each other through space. When this occurs, the partially negative portion of one of the polar molecules is attracted to the partially positive portion of the second polar molecule.
Van der Waals forces' is a general term used to define the attraction of intermolecular forces between molecules. There are two kinds of Van der Waals forces: weak London Dispersion Forces and stronger dipole-dipole forces.
The heat of fusion (heat required to melt a solid) and heat of vaporization (heat required to vaporize a liquid) are determined by the strength of the Intermolecular Forces. Substances with high IMF will have higher melting and boiling points. It will require more energy to break the IMF.
Intermolecular forces are forces between different molecules and include things like London dispersion forces, Van der Waals forces, and dipole-dipole interactions. Intramolecular forces are stronger because they involve the actual sharing of electrons for covalent bonds.
When the hydrogen bond is present between two atoms of two different molecules,then it is known intermolecular hydrogen bond. When the hydrogen bond is present between two atoms of the same molecule, then it is known as intramolecular hydrogen bond.
Hydrogen bonding isn't the only intermolecular force in alcohols. There are also van der Waals dispersion forces and dipole-dipole interactions. The hydrogen bonding and the dipole-dipole interactions will be much the same for all the alcohols, but the dispersion forces will increase as the alcohols get bigger.
Updated: 2nd October 2019