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  Avogadro's Number 

                                                                                                         

                                                                                                           
Amaedo Avogadro was born in 1776 and died 1856. It is an Italian scholar                                                                                                                      "Avogadro's Number is a collection of   6.02*10^23
                      particales.It is represented by symbols 'NA'
                      hence the  6.02*10^23 number of atom, molecules
                      or formula unit is callad Avogadro's number that 
                      is equivalent to one 'mole' of repecctive substance
                      In simple words 6.02*10^23 particles are equal to                             one mole as twelve eggs are equal to one donzen."

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 Neil Bohr

Neil Bohr was a Danish physics who joined Rutherford in 1912 for his post doctoral research. In 1913, Bohr presented his atomic model based upon Quantum theory.He won the 1922 Noble Prize for Physics for his work on the structure of an atom.

• Atom should exist.
• It was based upon quantum theory.
• Electrons revolve around the nucleus in orbits of fixed energy.
• Orbits had angular momentum.
• Atom should produce line spectrum.

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 Rutherford


Rutherford was a British New Zealand chemist.He performed a series of experiments using alpha particles. He won the 1908 Noble Prize in Chemistry. In 1911,he proposed the nuclear model of the atom and performed the first experiment to split atom.Because of his great con

 Rutherford's Atomic Model

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   J.J Thomson

 J.J Thomson was born in 1856 and died on 1940.He was a British physicist .He was awarded the 1906 Noble Prize in Physics for the discovery of electron and for his work on the conduction of electricity in gases. 
















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 Sir William Crooks



He was born in 1832 and died at 1919. He was a British chemist and physics. He was pioneer of vacuum tubes. He worked on spectrocopy.

           "He performed experiment by passing electric current                     through gases in a discharges  tube at very low                                   pressure.He took a glass tube fitted with two metallic                         electrod, which connected to a high voltag                                         battery.When high    voltag current was passed                                 through the gas,shiny rays were emitted from the                               cathod towards the anode .These rays called Cathode                       Rays."

•   Theserays travel in a straight lines perpendicular to the           cathode surface.
•   They rise a temperature of the body on which they fall.
•   Light is produced when these rays hit the walls of the               discharge tube.
•   J.J Thomson discoverd their charge/mass (e/m) ratio.
•   They can cast a sharp shadow of an apaque object if placed     in their path.

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     Goldstein

        In 1886 Goldstein observed that in addition to cathode rays, other rays were also present in the discharge tube.These rays were traveling in opposite direction to cathod rays.He used a discharge tube  having performed cathode.He found that these rays passed through holes present in the cathode and produced a glow on the walls of the discharge tube.He called these rays as "CANAL RAYS"

• These rays travel in straight line in a opposite to the cathod rays 
• The nature of canal rays depend upon the nayure of gas, present in the discharge tube.
• These rayss do not originate form the anode.

         
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Mendeleev

Dmitri Ivanovich Mendeleev was a Russian chemist and inventor. He formulated the Periodic Law, created his own version of the periodic table of elements, and used it to correct the properties of some 
Born: February 8, 1834, Tobolsk, Russia
Died: February 2, 1907, Saint Petersburg, Russia
Awards: Copley Medal, Demidov Prize
Education: Ruprecht Karl University of Heidelberg, Saint Petersburg State University
Siblings: Masha Mendeleeva
Books: Mendeleev on the Periodic Law: Selected Writings, 1869-1905, Gde Stroit' Neftyanye Zavody?
                                                                         
                      

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    Robert Boyle
                         "He observed that volume of a                                                              given mass of a gas is inversely
                                   proportional to its pressure                                                                  provided the temperature                                                                    remains constant."


Mathematically, Boyle's law can be stated as

P \propto \frac{1}{V}
or
 PV = k
where P is the pressure of the gas, V is the volume of the gas, and k is a constant.
The equation states that product of pressure and volume is a constant for a given mass of confined gas as long as the temperature is constant. For comparing the same substance under two different sets of condition, the law can be usefully expressed as

P_1 V_1 = P_2 V_2

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       J.Charles
                 J.Carles was born 1746 and died at 1823.He was a 
                 French inventor scientist,mathematician and                                      balloontist .He described in 1802 ,how gases tend 
                 toexpand when heated.  
                  
        "   The relationship between volume and temperature 
            keeping the pressure constant was also studied French
            scientist J.Charles.
            The volume of a given mass of a gas is directly                                   proportional to the absolute temperature if the pressure                     is kept constant".       
                
When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be directly related. [1]
this directly proportional relationship can be written as:
V \propto T\,
or

\frac{V}{T}=k
where:

V is the volume of the gas
T is the temperature of the gas (measured in Kelvin).
k is a constant.









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        Dalton


John Dalton was born on September 6, 1766 into a Quaker family in Eaglesfield in Cumberland, England and died on July 27, 1844.

            His atomic theory said that elements consisted of tiny                        particles called atoms. It states an element is one of a kind                (aka pure) because all atoms of an element are identical. All            the atoms that make up the element have the same mass. All            elements are different from each other due to differing                      masses. A compound is a pure (one of a kind) substance due            to different
        
         A photo of John Dalton's atomic model
        elements bonded together. They are not easily separated from           one another. Compounds have a fixed ratio of atoms. Each              atom has its own characteristic weight, creating a weight ratio          between elements. Also, his theory said that chemical reactions        involve the rearrangement of combinations of atoms. His                  atomic theory stated the general information on the atom.                Everything is made of atoms. All atoms of different substances        have different weights.


                              


 His atomic theory said that elements consist of tiny particles called atoms. It states an element is one of a kind (aka pure) because all atoms of an element are identical. All the atoms that make up the element have the same mass. All elements are different from each other due to differing masses. A compound is a pure (one of a kind) substance due to different A photo of John Dalton's atomic model elements bonded together. They are not easily separated from one another. Compounds have a fixed ratio of atoms. Each atom has its own characteristic weight, creating a weight ratio between elements. Also, his theory said that chemical reactions involve the rearrangement of combinations of atoms. His atomic theory stated the general information on the atom. Everything is made of atoms. All atoms of different substances have different weights.




KEY POINTS

• Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.
• Dalton also stated that all compounds were composed of combinations of these atoms in defined ratios.
• Dalton postulated that chemical reactions resulted in the rearrangement of the reacting atoms.

TERMS

1. atom

               the smallest possible amount of matter that still retains its                  identity as a chemical element, now known to consist of a                nucleus surrounded by electrons

1. atomic mass unit

              the standard unit that is used for indicating quantity on a                    molecular (or smaller) scale


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