CAN U PLEASE EXPLAIN WHAT IS CONDUCTION AND VALENCE BAND BECAUSE ATOM HAS INNER S ORBITALS AND OUTER WHICH ARE VALENCE ELECTRONS THEN IN SOLIDS WHERE ATOMS ARE CLOSELY PACKED IN A REPEATING PATTERN FROM WHERE BAND CAME AND FORBIDDEN ENERGY GAP PLEASE EXPLAIN THE CONCEPT WITH SOME 3D ANIMATOINS AS I VIDEOS?

Asked by Gaurav Avhad | 16th Mar, 2011, 12:49: AM

Expert Answer:

Dear student,
 
In an isolated atom the valence electrons can exist only in one of the allowed orbitals each of a sharply defined energy called energy levels. But when two atoms are brought nearer to each other, there are alterations in energy levels and they spread in the form of bands.
 
Valence band:The energy band formed by a series of energy levels containing valence electrons is known as valence band. At 0 K, the electrons fills the energy levels in valence band starting from lowest one.
 (i) This band is always filled by electrons.
ii) This is the band of maximum energy.
iii)Electrons are not capable of gaining energy from external electric field.
iv) No flow of current due to such electrons
v)The highest energy level which can be occupied by an electron in valence band at 0 K is called Fermi level.
 
Conduction band:The higher energy level band is called the conduction band.
 
(i) It is also called empty band of minimum energy.
ii)This band is partially filled by the electrons.
iii) In this band the electrons can gain energy from external electric field.
iv)The electrons in the conduction band are called the free electrons. They are able to move anywhere within the volume of the solid.
v)Current flows due to such electrons.
 
Hope this helps.
PLease get back to us for further clarifications.
Thankyou
Team
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Answered by  | 15th Mar, 2011, 10:28: PM

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