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SUBJECT-CHEMISTRY


                                           CHAPTER-ATOMIC STRUCTURE


               SUBTOPIC-ISOTOPES,ISOBARS,ISOTONES,EMR,PLANCK QUANTUM THEORY.

               KEY NOTES:


                     ISOTOPES :
                       Atoms of same element having same atomic number but different mass number are
                       called isotopes. Ex-protium, deuterium and tritium.
                     ISOBARS :
                       Atoms of different elements having different atomic number but same mass number
                       are called isobars.
                     ISOTONES :
                       Atoms of different elements having same number of neutrons in their nucleus are

                       called isotones.
                     Characteristics of electromagnetic waves :
                       Wavelength-The distance between any two consecutive crests or troughs is called
                                               wavelength.
                     Frequency -It is defined as the number of waves that pass a given point in one second.
                     Wave number-It is defined as the number of wavelengths per unit length.
                     Velocity-The linear distance travelled by the wave in one second.
                     Relationship between velocity, wavelength and frequency-
                                       
                                         c =  
                     PLANCK'S QUANTUM THEORY:
                       Postulates :
                            The radiant energy is emitted or absorbed not continuously but discontinuously
                              in the form of small discrete packets of energy.
                            Each packet of energy is called quantum and in case light it is called photon.
                            The energy of each quantum is directly proportional to the frequency of
                              radiation.
                            The total amount of energy emitted or absorbed by the body will be some whole
                              number quanta.
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