Difference between intermolecular and intramolecular forces

Key difference - intermolecular vs. intramolecular forces

Intermolecular and intramolecular forces are the two types of forces that hold individual molecules and atoms together. These forces control the movement of molecules and atoms. Both types of force determine the chemical and physical properties of substances. The main difference between intermolecular and intramolecular forces is that intermolecular forces exist between molecules themselves, while intramolecular forces exist between atoms within a molecule. In addition, there are many other differences between these forces.

This article examines

1. What are intermolecular forces? - definition, functions, properties

2. What are intramolecular forces? - definition, functions, properties

3. What is the difference between intermolecular and intramolecular forces?

Difference Between Intermolecular and Intramolecular Forces - Comparative Summary

What are intermolecular forces?

Intermolecular forces are forces that bind individual molecules in a substance due to their positive and negative charges. Intermolecular forces are attractive forces, but not chemical bonds. Thus, intermolecular forces are much weaker than intramolecular forces. These forces determine the physical properties of a substance. One of its most important physical properties is the ability to determine the state of a substance - whether solid, liquid or gaseous. These forces are responsible for the random movement of gases and the existence of liquids and solids as they hold liquid and solid molecules together. Therefore, intermolecular forces determine the melting and boiling point of matter. The melting or boiling point is proportional to the strength of the intermolecular forces. ie the higher the melting or boiling point, the stronger the intermolecular forces. At a given temperature, the strengths of the intermolecular forces of gas, liquid and solid are as follows.

Gas <liquid <solid

There are three types of intermolecular forces known as dipole-dipole forces, London dispersive forces, and hydrogen bonding forces. All of these bonds are created by electrical charges that result from the arrangement of electrons and nuclei in the molecules. Of the three types, hydrogen bonds are the strongest form of intermolecular bonds. Water molecules are held by hydrogen bonds due to the presence of partial charges at certain points on the molecules.

Difference between intermolecular and intramolecular forces

What are intramolecular forces?

Forces holding atoms in a molecule are called intramolecular forces. These forces are responsible for the formation of chemical bonds. Thus, intramolecular forces are much stronger than intermolecular forces. Intramolecular interactions occur when two atoms share electrons or give / gain electrons to / from another atom. When electrons are shared between two atoms, the bond is called a covalent bond . When an atom donates / gains an electron, the bond is called an ionic bond . Intramolecular forces determine chemical parameters of a substance. Metal bonds are also classified as a type of intramolecular force.

Key difference - intermolecular vs. intramolecular forces

Difference between intermolecular and intramolecular forces

definition

Intermolecular forces are the forces that hold molecules in a substance.

Intramolecular forces are the forces that hold atoms in a molecule.

strength

Intermolecular forces are weaker than intramolecular forces.

Intramolecular forces are stronger than intermolecular forces.

Determination of properties

Intermolecular Forces determine the physical state (solid / liquid / gas) and their physical properties such as melting / boiling point, etc.

Intramolecular forces determine the chemical behavior of a substance.

Nature of forces

Intermolecular forces are attractive forces.

Intramolecular forces are chemical bonds.

Examples

Intermolecular forces are divided into dipole-dipole forces, London dispersion forces and hydrogen bonding forces.

Intramolecular forces are divided into covalent, ionic and metal bonds.

Image courtesy:

“Ionic bonds” by BruceBlaus - Own work (CC BY-SA 4.0) via Commons Wikimedia

Reference:

Myers, R. The basics of chemistry . Np: Greenwood Publishing Group, 2003. Print.
CliffsNotes AP chemistry: with CD-ROM . Hoboken, NJ: Wiley, 2009. Print.
Kelter, PB, MD Mosher, and A. Scott. Chemistry: The practical science . vol. 10. Np: Cengage Learning, 2008. Print.
Rogers, DL, SR Goode, and DW Balle. Chemistry: principles and practice . Np: Cengage Learning, 2009. Print.

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