Structure Of Atom- Science Presentation
- 1. STRUCTURES OF ATOM B Y- A K S H U N C H A U H A N C L A S S - 9 D R O L L N O . - 2 8
- 2. Index 1. About Atom 2. JJ Thomson Model 3. Rutherford Model And Experiment 4. Neil Bohr's Model 5. Erwin Schrödinger Model 6. Question
- 3. Atoms and Sub-Atomic particles. • Atom is the fundamental unit of matter. • All forms of matter are made up of atom. Eg- Hydrogen(H), Oxygen(O). Sub atomic particles- I) Electron- Negatively charged II) Proton- Positively charged III) Neutron- Neural body
- 4. Thomson's Model Of Atom • JJ Thomson was the first to propose model of structure of atom. • As per his model, atom comprises a positively charged sphere with electrons embedded in it, (like a watermelon or plum pudding). • He explained that atom is neutrally charged as amount of positive and negative charge is equal.
- 5. His Study and Conclusion • He is credited for discovering the electron. • He used his research on cathode ray tube technology in this discovery.
- 6. Ernst Rutherford • Ernest Rutherford was not convinced about the model of the atom proposed by Thomson. • He thus set up his now famous Gold Foil Experiment.
- 7. Gold Foil α Particle Experiment 1. He fired alpha particles (positively charged) at a gold foil. 2. He measured the deflection as the particles came out the other side. 3. Most of the particles did not deflect at all. 4. He said that there must be a positive centre of the foil. He called this centre the nucleus.
- 8. RUTHERFORD’S ATOMIC MODEL • The nucleus of the atom is a dense mass of positively charged particles. • The electrons orbit the nucleus Drawbacks of his Model • As per Maxwell's theory of electro magnetics, when a charged particle is accelerated, it must loose energy. • In this case, if electrons loose energy, it will slow down and fall into the nucleus.
- 9. Neil Bohr • Niels Bohr agreed with the planetary model of the atom, but also knew that it had a few flaws. • Using his knowledge of energy and quantum physics he was able to perfect Rutherford’s model. • He was able to answer why the electrons did not collapse into the nucleus.
- 10. BOHR’S ATOMIC MODEL 1. Electrons orbit the nucleus in orbits that have a set size and energy. 2. The lower the energy of the electron, the lower the orbit. 3. This means that as electrons fill up the orbitals, they will fill the lower energy level first. 4. If that energy level is fill (or at capacity), a new energy level will begin.
- 11. Conclusion Bohr estimated the distance of shell from the nucleus. He gave the velocity of electrons in different shells. He also estimated the value of enrgy in different shells.
- 12. Schrödinger Model (Cloud Model) Erwin Schrödinger was a revolutionary physicist who used Heisenberg’s uncertainty principle to come up with the atomic model that we still use today. Conlcusion- 1. An electron does not travel in an exact orbit 2. We can predict where it will probably be 3. We cannot say for certain where it is, but only where it ought to be. 4. The type of probability orbit is dependent on the energy level described by Bohr
- 13. Questions