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Friday, May 28, 2010

Modern atomic theory

Modern atomic theory:
Based on:
(Wave-Particle Dualism) the dual nature of the electron
Heisenberg Uncertainty Principle


Finding the mathematical expression that describes:
Wave motion of electron
Shape and energy of that wave motion
The dual nature of the electron: experimental data showed that the electron has a dual nature which means that it has:
A wave property
A particle property
This means that: {Every moving body such as electron – nucleus – molecules is associates with a wave motion or matter waves known as (MATTER WAVES) which have properties differ from electromagnetic waves}
The matter wave motion differs from the electromagnetic waves in
Matter waves:
They are not separating from moving body
Their speed is not = speed of light  
Electromagnetic waves:
They are separating from moving body
Their speed is = speed of light
Heisenberg Uncertainty Principle: Bohr's atomic model postulated that it is possible to determine both the position (location) and the velocity of the electron at the same time
BUT
By applying the principles of quantum mechanics Heisenberg concludes that:
{It is impossible to determine both the position and velocity of the electron exactly at the same time}. 
We can only say it is probably to a greater or loser extant to locate the electron in this or that place Because if we image that the electron moves with certain velocity in certain direction, we must use photon to measure its position, and then this photon will change the velocity of the electron
Schrödinger mathematical expression: He uses the ideas of Blank, Einstein, De Broglie and Heisenberg to show that:
It is possible to determine the allowed energy level (orbital) of the electron
It is possible to define the region of space around the nucleus where it is most probable to find the electron in each orbital
The motion of electron around the nucleus has wave properties, therefore it is prefer to use the term of electron cloud to describe orbital
Electron cloud: It is the region of space around the molecules where it is probable to find the electron in it
Difference between orbit and orbital:
Orbit
Used in Bohr's theory
Circular planer with particular radii
It has a constant value It has not a constant value
Orbital
Used in Schrödinger's wave mechanics theory
Its radius is not constant
It has not a constant value

1 comments:

Leslie Lim said...

Nice post. I enjoy reading your article. I found new ideas and very good information. I will come back for the next post. Thank you.

Taylor
www.imarksweb.org

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