atomic struture and radioactivity
TRANSCRIPT
Discovery of nucleusDiscovery of nucleus&&
Theory of atomic Theory of atomic disintegrationdisintegration
ERNEST RUTHERFORD: FATHER OF NUCLEAR SCIENCE• Work-• He worked as a research student
under J.J.Thomson.• In 1898 he reported existance of
alpha particle in uranium radiation.
• In collaboration with Soddy developed theory of atomic disintegration.
• Steered other future noble prize winner towards their achievements e.g. Chadwick etc.
1871-1937
•Radioactive decay unit Rutherford(rd) was given on the name of Rutherford.•Rutherfordium(Rf,Z-104) was named on the name of Rutherford.•Many countries issued stamps and currency with his photo
CURRENCY ISSUED BY CURRENCY ISSUED BY NEWZEALANDNEWZEALAND
STAMP ISSUED BY DIFFERENT STAMP ISSUED BY DIFFERENT COUNTRIESCOUNTRIES
Rutherford’s Apparatus
Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 120
beam of alpha particles
radioactive substance
fluorescent screencircular - ZnS coated
gold foil
What he expected…
California WEB
What he got…richochetingalpha particles
• Hit moth driving car – no change in car direction
• Hit deer – car changes direction
Alpha particle
Large angle of deflection, must have hit massive object!
moth
deer
Gold Atom
DRAWBACKS OF RUTHERFORD MODEL..
• Stability of nucleus• Well defined lines of spectrum of
different frequency• The theory was unable to explaine the
distribution of electron in the atom
WHAT HOLDS A NUCLEUS WHAT HOLDS A NUCLEUS TOGETHERTOGETHER..
•
A strong nuclear force
BINDING ENERGY
THEORY OF DISINTEGRATION
• nuclei of Radioactive element are unstable.
• Disintegration is spontaneous.• During disintegration elements physical and chemical property changes.
• During disintegration alpha or beta particles are emmited.
•
ALPHA DECAY
BETA DECAY
ELECTRON CAPTUREELECTRON CAPTURE
3 reasons why we should stop using nuclear energy• Nuclear weapon proliferation
• Nuclear waste and energy• Accident and disasters