(a)
Interpretation:
From the given pictures, the material that relates to it has to be identified.
Concept introduction:
Semiconductor: A material which can conduct electricity in range between a metal and an insulator is known as semiconductor. Addition of small amount of impurities increases conductivity of semiconductor and the process is known as doping. n-type and p-type are two types of doped semiconductors.
n-type: This is a type of doped semiconductor in which many free electrons are present in conduction band.
p-type: This is a type of doped semiconductor in which holes are present in conduction band.
Insulator: Insulators are one, in which electrons are filled in valence band with a vacant conduction band and they are parted away by band gap.
Figure 1
(b)
Interpretation:
The ascending order of electrical conductivity of given materials has to be arranged and explained.
Concept introduction:
Semiconductor: A material which can conduct electricity in range between a metal and an insulator is known as semiconductor. Addition of small amount of impurities increases conductivity of semiconductor and the process is known as doping. n-type and p-type are two types of doped semiconductors.
n-type: This is a type of doped semiconductor in which many free electrons are present in conduction band.
p-type: This is a type of doped semiconductor in which holes are present in conduction band.
Insulator: Insulators in which electrons are filled in valence band with a vacant conduction band and they are parted away by band gap. Insulators does not conduct electricity.
(c)
Interpretation:
The effect of increase in temperature on the conductivity of given material has to be given.
Concept introduction:
Semiconductor: A material which can conducts electricity in range between a metal and an insulator is known as semiconductor. Addition of small amount of impurities increases conductivity of semiconductor and the process is known as doping. n-type and p-type are two types of doped semiconductors.
n-type: This is a type of doped semiconductor in which many free electrons are present in conduction band.
p-type: This is a type of doped semiconductor in which holes are present in conduction band.
Insulator: Insulators in which electrons are filled in valence band with a vacant conduction band and they are parted away by band gap. Insulators does not conduct electricity.
Effect of change in temperature: Increase in temperature increases electrical conductivity of semiconductors because when temperature raises, there will be more electrons in conduction band and hole in valance band. On the other hand, electrical conductivity decreases when temperature increases due to increased vibrational motion of metal cation around lattice leads to disruption of flow of electrons in crystal.
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Chapter 21 Solutions
General Chemistry: Atoms First
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