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Intramolecular and intermolecular forces

When atoms join to form molecules, they are held together by chemical bonds . The type of bond, and the strength of the bond, depends on the atoms that are involved. Thesebonds are called intramolecular forces because they are bonding forces inside a molecule ('intra' means 'within' or 'inside'). Sometimes we simply call theseintramolecular forces chemical bonds.

Intramolecular force

The force between the atoms of a molecule, which holds them together.

Examples of the types of chemical bonds that can exist between atoms inside a molecule are shown below. These will be looked at in moredetail in Grade 11.

  • Covalent bond Covalent bonds exist between non-metal atoms e.g. There are covalent bonds between the carbon and oxygen atoms in a molecule of carbon dioxide.
  • Ionic bond Ionic bonds occur between non-metal and metal atoms e.g. There are ionic bonds between the sodium and chlorine atoms in a molecule of sodium chloride.
  • Metallic bond Metallic bonds join metal atoms e.g. There are metallic bonds between copper atoms in a piece of copper metal.

Intermolecular forces are those bonds that hold molecules together. A glass of water for example, contains many molecules of water. These molecules are held together byintermolecular forces. The strength of the intermolecular forces is important because they affect properties such as melting point and boiling point . For example, the stronger the intermolecular forces, the higher the melting pointand boiling point for that substance. The strength of the intermolecular forces increases as the size of the molecule increases.

Intermolecular force

A force between molecules, which holds them together.

The following diagram may help you to understand the difference between intramolecular forces and intermolecular forces.

Two representations showing the intermolecular and intramolecular forces in water: space-filling model and structural formula.

It should be clearer now that there are two types of forces that hold matter together. In the case of water, there are intramolecularforces that hold the two hydrogen atoms to the oxygen atom in each molecule of water (these are the solid lines in the above diagram). There are also intermolecular forces between each of these water molecules . These intermolecular forces join the hydrogen atom from one molecule to the oxygenatom of another molecule (these are the dashed lines in the above figure). As mentioned earlier, these forces are veryimportant because they affect many of the properties of matter such as boiling point, melting point and a number of other properties. Before we go on to look at some of these examples, it is importantthat we first take a look at the Kinetic Theory of Matter .

Intramolecular and intermolecular forces

  1. Using ammonia gas as an example...
    1. Explain what is meant by an intramolecular force or chemical bond .
    2. Explain what is meant by an intermolecular force.
  2. Draw a diagram showing three molecules of carbon dioxide. On the diagram, show where the intramolecular and intermolecular forcesare.
  3. Why is it important to understand the types of forces that exist between atoms and between molecules? Try to use some practical examples in your answer.

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Siyavula textbooks: grade 10 physical science. OpenStax CNX. Aug 29, 2011 Download for free at http://cnx.org/content/col11245/1.3
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