J.J. Thomson Model Atom consists of positively charged matter with electron embedded on it Positively charged matter

Geiger and Masden Experiment Some alpha particles are deflected => There must be a very heavy particles,  It can not be electrons because alpha particle mass is about 8000 times mass.

Rutherford Model

Rutherford Scattering

Remember some formulas x  y  pp Angular momentum: Electric Force Between alpha particles and nucleus

Nuclear Dimensions Rutherford assumed the nucleus size is smaller compared to the minimum distance of alpha particles approaches nucleus before deflected At closest point R, all kinetic particles is converted to electric potential energy R is ussually predicted as maximum the nucleus size Fraction of incident alpha scattered by  or more Number of alpha particle per unit are striking screen at 

Weakness of Rutherford Model +Ze -e

Electron Orbit Condition for a dynamically stable orbit of hidrogen atom + -e v r

Bohr Model An electron can circle a nucleus only if its orbit contains an integral number of de Broglie wavelenghts Condition for orbit stability Orbital radii in Bohr atom Bohr radius Energy levels

Atomic Spectra Ground state excitation hf emission Source: Source: 5e.plantyphys.net

Hydrogen Series Rydberg constant: Lyman Series: Balmer Series: Pachen Series Bracket Series Pfund Series

Source: www. astro.cornell.edu

Source: chemed.chem.purdue.edu High voltage + -

Light Interaction with atom hf absoption hf Spontaneous emission hf Stimulated emission hf Stimulated emission

Laser (Light amplification by stimulated emission of radiation) Population inversion fast decay hf

He-Ne Laser Source: hyperphysics.phy-astr.gsu.edu Source:

Semiconductor Laser

Surce: