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We begin as a starting point with the atomic molecular theory. We thus assume that most of the common elementshave been identified, and that each element is characterized as consisting of identical, indestructible atoms. We also assume thatthe atomic weights of the elements are all known, and that, as a consequence, it is possible via mass composition measurements todetermine the molecular formula for any compound of interest. In addition, we will assume that it has been shown by electrochemicalexperiments that atoms contain equal numbers of positively and negatively charged particles, called protons and electronsrespectively. Finally, we assume an understanding of the Periodic Table. In particular, we assume that the elements can be groupedaccording to their common chemical and physical properties, and that these chemical and physical properties are periodic functionsof the atomic number.


The atomic molecular theory is extremely useful in explaining what it means to form a compound from itscomponent elements. That is, a compound consists of identical molecules, each comprised of the atoms of the component elements ina simple whole number ratio. However, our knowledge of these atoms is very limited. The only property we know at this point is therelative mass of each atom. Consequently, we cannot answer a wide range of new questions. We need a model which accounts for theperiodicity of chemical and physical properties as expressed in the Periodic Table. Why are elements which are very dissimilar inatomic mass nevertheless very similar in properties? Why do these common properties recur periodically?

We would like to understand what determines the number of atoms of each type which combine to form stablecompounds. Why are some combinations found and other combinations not observed? Why do some elements with very dissimilar atomicmasses (for example, iodine and chlorine) form very similar chemical compounds? Why do other elements with very similar atomicmasses (for example, oxygen and nitrogen) form very dissimilar compounds? In general, what forces hold atoms together in forming amolecule?

Answering these questions requires knowledge of the structure of the atom, including how the structures of atomsof different elements are different. Our model should tell us how these structural differences result in the different bondingproperties of the different atoms.

Observation 1: scattering of α particles by atoms

We have assumed that atoms contain positive and negative charges and the number of these charges is equal inany given atom. However, we do not know what that number is, nor do we know how those charges are arranged inside the atom. Todetermine the location of the charges in the atom, we perform a "scattering" experiment. The idea is straightforward:since we cannot "see" the atomic structure, then we instead "throw" things at the atom and watch the way inwhich these objects are deflected by the atom. Working backwards, we can then deduce what the structure of the atom must be.

Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Concept development studies in chemistry. OpenStax CNX. Dec 06, 2007 Download for free at http://cnx.org/content/col10264/1.5
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