Atomic structure

1. ATOMIC STRUCTURE Presented by Nandlal and Gaurav

2. The existence of atoms has been proposed since the times of early I ndian and greek phylosophers around 400 b.C. An I ndian phylosopher maharshi kanad postulated that if we go on dividing matter (padarth), we shall altimately get smallest particle beyond which further divisions will not possible. He named these particles as PARMANU. Around same era, ancient greek phylosophers democritus and leucippus suggested that if we go on dividing matter, a stage will come when particles obtained cannot be devided further. However , all these ideas were based on phylosophical considerations and not very experimental .

3. DALTON’S POSTULATES Matter consist of indivisible particle. Atoms of same elements are same. Atoms always combine in simple whole number ratio. It can neither be created nor destroyed. Atoms of different elements are different.

4. Dalton theory limitation Dalton stated that matter is made of indivisible Particle atom but later it proved wrong as it was found that Atom is further made of proton electron and neutron. Electron neutron Proton

5. DISCOVERY OF CONSTITUTE PARTICLE OF ATOM When electric current of 10000v to 20000v passes through cathode to anode an electron of gas present in tube move toward anode plate. ELECTRON CATHODE RAY MODAL CATHODE ANODE VACCUM PUMP CATHOD TUBE

6. PROPERTIS OF CATHODE RAY These rays » originate from cathode » travel in straight line »exert mechanical pressure » deflected by magnetic field » carry negative charge

7. ANODE RAY MODEL Cathode Anode H 2 WHEEL

8. Ray move toward cathode plate. Colour of the glowing depends on nature ofgas . These travel in straight line and have Mechanical energy. Properties of A node ray

9. Particle Mass Charge Discover by Electron Proton Neutron

10. electron proton FIRST ATOMIC MODEL PRAPOSED BY J.J THOMSON Plum pudding model

11. RUTHERFORD ATOMIC MODEL GOLD FOIL PHOTOGRAPHIC PLATE SOURCE OF ALPHA PARTICLES LEAD PLATE RUTHERFORD’S SCATTERING EXPRIMENT

12. Path of the Rays DEFLECTED RAY STRAIGHT RAY GOLD FOIL MOST OF THE ALPHA –PARTICLE PASSED THROUGH THE GOLD FOIL UNDEFLECTED. SMALL FRACTION OF THE ALPHA PARTICLE WERE DEFLECTED BY SMALL ANGLES A VERY FEW ALPHA PARTICLE (~1 IN 20,000 ) BOUNCED BACK,THIS IS, WERE DEFLECTED BY NEARLY 180º DEFLECTED BACK

13. ATOM HAS THREE FUNDAMMENTAL PART ELECTRON, PROTON, NUTRON. ELECTRON MOVE AROUND THE NUCLEUS. HOLE MASS OF THE ATOM CONCENTRATED IN THE CENTER OF NUCLEOUS. NUCLEUS IS ABOUT 10 SMALLER THEN ATOM. 5 NUCLEOUS IS POSITEVELY CHARGED.

14. Ruther ford modal and its draw back Stability of atom could not be defined How many electron revolve in an orbit ?

15. ELECTROMAGNETIC SPECTRUM VISIBLE RANGE X RAYS UV IR MICROWAVES FM AM RADIO WAVES LONG RADIO WAVES ɤ RAYS

16. A AMMETER VACCUM CHAMBER ELECTRONS LIGHT METAL SURFACE + - DETECTER PHOTOELECTRIC EFFECT

17. 20 th century: Max Planck proposed quantum physics to explain the behavior of subatomic particles

18. R ules Governing the Allowed Combinations of Quantum Numbers The three quantum numbers ( n ,  l , and  m ) that describe an orbital are integers: 0, 1, 2, 3, and so on. The principal quantum number ( n ) cannot be zero. The allowed values of  n  are therefore 1, 2, 3, 4, and so on. The angular quantum number ( l ) can be any integer between 0 and  n  - 1. If  n  = 3, for example,  l  can be either 0, 1, or 2. The magnetic quantum number ( m ) can be any integer between - l  and + l . If  l  = 2,  m  can be either -2, -1, 0, +1, or +2. QUANTUM NO’s

19. AUFBAU PRINCIPLE The orbitals are filled according to the increasing energies of the orbital

20. Hund's rule : every orbital in a sub shell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbital's have the same spin. HUND’S RULE

21. Electronic configuration

22. DIRECTED BY VINITA SHARMA PRODUCED BY POONAM JI MADE BY NANDLAL AND GAURAV GLT SARASWATI BAL MANDIR NEHRU NAGAR THE END