Quantum mechanical model of an atom

Based on Quantum mechanics (i.e. new branch of physics) applicable to microscopic particles. Quantum mechanic developed by Erwin Schrodinger based on wave motion associated with particles.

In this model, the wave motion of electron in three dimensional space around the nucleus in an atom is describe by an equation known as Schrodinger wave equation.

x y z = Three space coordinates

m = mass of electron h = Plauk’s constant  E = total energy of the electron.                                 V = potential energy of the electron.

Ñ° (PSI) a aptitude of wave (no physical significance)  =  Second derivative functions w.r.t. to x axis  Ñ°2 = gives intensity of electron wave ( has physical significance ) i.e. give orbital picture or probability of finding the electron at that point.

Orbital – Three dimensional space around the nucleus within which the probability of finding an electron in given energy is max (say up to 90%)

Orbit	Orbital
(1) Well defined circular path around the nucleus in which electrons revolve.	(1) def.
(2) It represents the planar motion of electron ground nucleus.	(2) Three dimensional motion
(3) All orbits are circular +disc like	(3) different shape
(4) it can accommodate            2u2 electron            U= principle	(4) It can accommodate 2 electrons.

Important feature of Quantum mechanical model

(1)  Electrons in an atom have only quantized value of energy.

(2)  Quantized value of energy obtained from solution of Schrodinger wave equation.

(3)  Ψ has no physical significance but Ψ²  gives the probability  of finding the electron( i.e. electron density)

(4)  Ψ² predict the region of space around the nucleus, where probability of finding the electron is max called orbital.

(5)  An electron can have many wave functions therefore, these are many atomic orbital an atom.

(6)  Orbital gives all information of electron in an atom.