Skip to main content

Unit 1 Atomic structure


Idea of De-broglie matter waves

 Einstein in 1905 suggested that light has dual character . 
In 1924 De-broglie proposed that matter also has dual character ( it means behave as waveas well as particle)  .

 Principle:  The principal of wave and particle duality of matter is known as De- broglie principle. 

 If substance behavea particle it's energy is given by Einstein 

       E= mc^2     1eq.
 if substance behave like a wave it's energy given by plancks quantum theory. 

       E= hv           2eq. (here v is called nue  ) 
from 1 & 2 eq. 

we get hv=mc^2

  & also know v= c/√ 

 let is √ called lamda  

 now (h×c) /√ =mc^2

or √= h/m×c

 Applying relation to an eletron moving with velocity(V). 

  so √= h/m×V

&we know that p= m×V

        or √= h/p

This relation is called De-broglie wave eq

 Significance of de broglie Relationship
 In our daily life we come across with macroscopic object so De- broglie relationship has no significance in our daily life. 

 De-broglie relationship is applicable to all moving particle but it is significance to microscopic particle ,because just
    √ { 1/m                ( where { called directly proportional sign) 

1. for macroscopic particle since mass is large . so √  comes out too be small, not to be measured .

2. for microscopic particle since mass is small,.  so √ comes out to be large & can  be measured experimently. 
   
see next page

Comments

Popular posts from this blog

Radial probability distribution for p and d orbital, radial wave functions

Radial probability distribution for p and d orbital Radial and Angular wave function:  the radial part of wave function depends upon quantum no.  n and  l  and gives the distribution of electron w. r. t distance .it is governed mainly exponential term     e^-Zr/na°(a not)   here  e   based on natural log.  Z   Atomic number r     distance from nucleus  n    principal quantum no. or radial quantum           no.  a°    0.529A° for hydrogen  ( Bohr radii)  the exact mathematical expression for radial part of wave function for 1s or 2s and 2p orbitals. n= 1 ,l=0 s orbital    R(r) =2× (z/a°) ^3/2 ×(2-zr/a°) ×e^-zr/2a° n= 2 ,l=0 2s orbital    R(r) = (z/a°) ^3/2 ×(2-zr/a°) ×e^-zr/2a° n= 2 ,l=1 2p orbital    R(r) = 1√3×(z/2a°) ^3/2 ×(zr/a°) ×e^-zr/2a ° the rad...

Radial probability distribution curves

Radial probhjjhajajbability distribution curves:  The probability of finding the electron is given by the quantity  sie^2.By radial probability us probability of finding the electron within small Radial space around the nucleus. volume of spherical shell between radius r and r+dr =4πr^2 and probability of finding the electron will be 4πr^2dr sie^2. radial probability distribution curves are obtained by plotting radial probability at various distance from the nucleus . 1.Radial probability distribution curves for S orbital n=1, l= 0. distance from nucleus here A° is called angstrom. the probability of finding of electron in a shell is maximum at distance r=r° (r not)  which is 0.529 A° for H atom. diagram shows that probability plot for 2s has(two region of high probability)  or (two peaks)  separated by node. we conclude that  no.  of high probability region in S orbital = n no.  of node = ( n-1) 

Linear combination of atomic orbital, Molecular orbital theory, Difference between bonding & anti bonding moleculer orbital.

Linea combination of atomic orbital  molecular orbital are formed by combination of atomic orbital  if ꌏ(A)  andꌏ(B)  are the wave function of atomic orbital of two combining atomic A and B  then according  to Linea combination of atomic orbital, these two wave function can be added or can be substracted .that means there are two modes of interaction (symmetric and antisymmetric)  We know ꌏ(s)  = ꌏ(A) +ꌏ(B)  ꌏ(a) = ꌏ(A)- ꌏ(B) ꌏ(s)  and ꌏ(a)  represent wave function of bonding and antibonding moleculer orbital. the formation of moleculer orbital ꌏ(s)  and ꌏ(a)  from two atomic orbital ꌏ(A) and ꌏ(B)  is represented as Molecular orbital theory (MO)  theory: main points of mo theory are: 1.whwn atomic orbital combine they formed molecular orbital. 2.Number of molecular orbital formed is equal to number of atomic orbital combine. 3.atomic orbital are uninuclear  while molecular orbital  a...