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Briefly explain how impurities are selected for doping in group 14 semiconductors.

This process is known as doping. It can be done by adding either of two types of impurity to the crystal. (A) By adding electron rich impurities i.e., group 15 elements to the silicon and germanium of group 14 elements.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.