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There is a very interesting consistency in these molecular formulae: in each case, the number of hydrogen atoms is two more than twice the number of carbon atoms, so that each compound has a molecular formula like C n H 2n+2 . (Try it out!) This suggests that there are strong similarities in the valences of the atoms involved which should be understandable in terms of our valence shell electron pair sharing model.

Since each H atom can only bond to a single other atom, the carbon atoms in each molecules must be directly bonded together. In the easiest example of ethane, the two carbon atoms are bonded together, and each carbon atom is in turn bonded to three hydrogen atoms. This would fit our model of valence, since each carbon atom is bonded to four other atoms (three hydrogens and the other carbon). By sharing an electron pair with each of those four atoms, each carbon atom fills its valence shell with eight electrons. This example was not difficult.

In most other cases, it is not so trivial to determine which atoms are bonded to which. This is because there may be multiple possibilities which satisfy all the atomic valences. As the number of atoms and electrons increases, it may also be difficult to determine whether each atom has an octet of electrons in its valence shell. We need a system of counting the valence electrons which makes it easy for us to see these features more clearly. To start, we create a notation for each atom which displays the number of valence electrons in the unbonded atom explicitly. In this notation, carbon and hydrogen look like

where the dots represent the single valence electron in hydrogen and the four valence electrons in carbon. Note that the C atom valence electrons are all unpaired. This is because we know that the valence of a C atom is four, so there are four valence electrons available to be shared with other atoms.

Using this notation, it is now fairly easy to represent the shared electron pairs and the carbon atom valence shell octets in methane and ethane. For each pair of bonded atoms, we share an electron pair from the valence shell electrons. This gives for methane and ethane:

Recall that each shared pair of electrons represents a chemical bond. These drawing are examples of what are called “Lewis structures,” after G.N. Lewis who first invented this notation. These structures reveal, at a glance, which atoms are bonded to which, so we call this the “structural formula” of the molecule. There are two things to check about the electrons in the structural formula. First, we cannot have created or lost any valence electrons. For example, in ethane we started with four valence electrons from each carbon and one valence electron from each hydrogen, for a total of 14 electrons. The structural formula of ethane drawn above has 14 valence electrons, so that is correct. Second, if we have satisfied the valence of each atom, each carbon should have an octet of electrons and each hydrogen should have two electrons. We can also easily count the number of valence shell electrons around each atom in the bonded molecule and verify that this is also correct.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
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
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
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
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
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
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Source:  OpenStax, Concept development studies in chemistry 2013. OpenStax CNX. Oct 07, 2013 Download for free at http://legacy.cnx.org/content/col11579/1.1
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