Carbon, silicon and germanium have four valence electrons each. At roo...
Si and Ge are semiconductors but C is an insulator.
Also, the conductivity of Si and Ge is more than C because the valence electrons of Si, Ge and C lie in third, fourth and second orbit respectively.
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Carbon, silicon and germanium have four valence electrons each. At roo...
Explanation:
To understand why option 'A' is the correct answer, we need to consider the electronic structure and bonding in carbon, silicon, and germanium.
1. Valence Electrons:
- Carbon, silicon, and germanium all belong to Group 14 of the periodic table, which means they have four valence electrons each.
- Valence electrons are the electrons in the outermost shell of an atom and are involved in bonding.
2. Electronic Configuration:
- The electronic configuration of carbon, silicon, and germanium can be represented as follows:
- Carbon: 1s² 2s² 2p²
- Silicon: 1s² 2s² 2p⁶ 3s² 3p²
- Germanium: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p²
- In their ground state, all three elements have completely filled valence shells.
3. Bonding:
- Carbon, silicon, and germanium are all tetravalent elements, meaning they can form four covalent bonds by sharing electrons.
- In each of these elements, the four valence electrons participate in bonding, forming a stable structure.
- Carbon forms covalent bonds in molecules, silicon forms covalent bonds in extended structures like silicon crystal, and germanium also forms covalent bonds in extended structures similar to silicon.
4. Conduction:
- In order for a material to conduct electricity, it must have mobile charge carriers, typically electrons or ions.
- In carbon, each carbon atom forms four covalent bonds, resulting in a stable structure with no free electrons available for conduction.
- In silicon and germanium, the situation is different. Although silicon and germanium also form covalent bonds, their crystal structures allow for the presence of free electrons.
- At room temperature, silicon and germanium have enough thermal energy to promote some electrons from the valence band to the conduction band, creating free electrons for conduction. This makes the number of free electrons for conduction significant in silicon and germanium.
Hence, the statement in option 'A' is the most appropriate. The number of free electrons for conduction is significant only in silicon and germanium but small in carbon.
Carbon, silicon and germanium have four valence electrons each. At roo...
Option A is correct...
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