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In the case of metals the valence and conduction bands have
  • a)
    no overlap, energy gap is large
  • b)
    no overlap, energy gap is small
  • c)
    overlap, energy gap =0
  • d)
    no overlap, energy gap =0
Correct answer is option 'C'. Can you explain this answer?
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In the case of metals the valence and conduction bands havea)no overla...
The materials can be classified by the energy gap between their valence band and the conduction band. The valence band is the band consisting of the valence electron, and the conduction band remains empty. Conduction takes place when an electron jumps from valence band to conduction band and the gap between these two bands is forbidden energy gap. Wider the gap between the valence and conduction bands, higher the energy it requires for shifting an electron from valence band to the conduction band.In the case of conductors, this energy gap is absent or in other words conduction band, and valence band overlaps each other. Thus, electron requires minimum energy to jump from valence band. The typical examples of conductors are Silver, Copper, and Aluminium.In insulators, this gap is vast. Therefore, it requires a significant amount of energy to shift an electron from valence to conduction band. Thus, insulators are poor conductors of electricity. Mica and Ceramic are the well-known examples of insulation material. Semiconductors, on the other hand, have an energy gap which is in between that of conductors and insulators. This gap is typically more or less 1 eV, and thus, one electron requires energy more than conductors but less than insulators for shifting valence band to conduction band.
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In the case of metals the valence and conduction bands havea)no overla...
In the case of metals, the valence and conduction bands overlap with each other, and the energy gap between them is zero. This means that the valence band and the conduction band are not separated by an energy gap in metals.

Explanation:
1. Valence band: The valence band is the band that contains the highest energy levels occupied by electrons in a material at absolute zero temperature. It represents the energy levels of the valence electrons, which are responsible for the bonding and electrical properties of the material.

2. Conduction band: The conduction band is the band that contains the lowest unoccupied energy levels in a material. Electrons in this band are free to move and contribute to the electrical conductivity of the material.

3. Energy gap: The energy gap is the difference in energy between the valence band and the conduction band. In insulators and semiconductors, there is a significant energy gap between these two bands, which prevents the free movement of electrons and leads to poor electrical conductivity. However, in metals, this energy gap is zero.

4. Overlap of valence and conduction bands: In metals, the valence and conduction bands overlap with each other. This means that there is a continuous range of energy levels available for electrons to occupy, both in the valence band and the conduction band. As a result, electrons can easily transition from the valence band to the conduction band by absorbing or releasing a small amount of energy.

5. Free movement of electrons: The overlap between the valence and conduction bands allows electrons in metals to move freely throughout the material. This leads to high electrical conductivity in metals, as electrons can easily carry electric charges from one atom to another.

In summary, in metals, the valence and conduction bands overlap with each other, and the energy gap between them is zero. This allows for the free movement of electrons and contributes to the high electrical conductivity of metals.
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In the case of metals the valence and conduction bands havea)no overlap, energy gap is largeb)no overlap, energy gap is smallc)overlap, energy gap =0d)no overlap, energy gap =0Correct answer is option 'C'. Can you explain this answer?
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