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Atomic structure
The document discusses the history of the discovery of atoms and their components. It begins with ancient Indian and Greek philosophers proposing the earliest ideas of atoms in 400 BC. In the early 1900s, scientists like J.J. Thomson discovered the electron through cathode ray experiments. Ernest Rutherford then used the gold foil experiment to show that atoms have a small, dense nucleus. This led to the modern understanding that atoms consist of a small, positively charged nucleus surrounded by electrons. Quantum physics, developed by Max Planck and others in the early 20th century, was necessary to fully explain the behavior of subatomic particles.
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Atomic structure
- 2. The existence ofatoms has been proposed since the times of early Indian and greek phylosophers around 400 b.C. An Indian 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 .
- 4. Dalton stated thatmatter 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.
- 6. These rays » originatefrom cathode » travel in straight line »exert mechanical pressure » deflected by magnetic field » carry negative charge
- 11. GOLD FOIL PHOTOGRAPHIC PLATE SOURCEOF ALPHA PARTICLES LEAD PLATE
- 12. DEFLECTED RAY STRAIGHT RAY GOLDFOIL 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 THREEFUNDAMMENTAL 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. NUCLEOUS IS POSITEVELY CHARGED.
- 16. X RAYS UVIR FM AM RADIO WAVES LONG RADIO WAVES ɤ RAYS
- 17. A AMMETER VACCUM CHAMBER ELECTRONS LIGHT METALSURFACE + - DETECTER
- 18. 20th century: Max Planck proposed quantumphysics to explain the behavior of subatomic particles
- 19. Rules Governing theAllowed 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. cannot be zero. The allowed values of n are therefore 1, 2, 3, 4, and so on. can be any integer between 0 and n - 1. If n = 3, for example, l can be either 0, 1, or 2. can be any integer between -l and +l. If l = 2, m can be either -2, -1, 0, +1, or +2.
- 20. The orbitals arefilled according to the increasing energies of the orbital
- 22. Hund's rule: everyorbital 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.