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Difficulty: MediumConductors, Insulators, and Semiconductors

An electronics technician is organizing bench materials according to their ability to conduct electrical current under standard room temperature conditions. Arrange the following materials in sequence from highest electrical conductivity (easiest current flow) to lowest electrical conductivity (highest opposition to current flow).

  1. 1Silver
  2. 2Aluminum
  3. 3Germanium
  4. 4Teflon (PTFE)

Answer

The correct sequence from highest to lowest conductivity is Silver, Aluminum, Germanium, and Teflon.
Electrical conductivity depends directly on the availability of free valence electrons to transport charge. Silver possesses the highest conductivity among all metals due to its single, loosely held valence electron per atom. Aluminum is also an effective conductor but has higher resistivity than silver. Germanium is a semiconductor containing four valence electrons, resulting in intermediate conductivity. Teflon is an excellent insulator with tightly bound electrons in stable covalent bonds, exhibiting negligible conductivity.

Step-by-Step Solution

1
Identify the metallic conductors and determine their relative conductivity
Silver has the highest electrical conductivity of all metals (6.3×107 S/m6.3 \times 10^7\text{ S/m}), followed by Aluminum (3.7×107 S/m3.7 \times 10^7\text{ S/m}).
Conductors have free valence electrons that drift easily under an electric field, with silver offering less resistance than aluminum.
2
Identify the semiconductor material and evaluate its conductivity level
Germanium has four valence electrons forming a crystal lattice, giving it an intermediate conductivity (≈2 S/m\approx 2\text{ S/m}).
Semiconductors have conductivities between those of conductors and insulators at room temperature.
3
Identify the insulator and evaluate its conductivity level
Teflon has extremely tightly bound valence electrons and near-zero conductivity (<10−15 S/m< 10^{-15}\text{ S/m}).
Insulators lack free charge carriers, preventing current flow under normal operating conditions.
4
Assemble the complete sequence from greatest conductor to greatest insulator
Silver →\rightarrow Aluminum →\rightarrow Germanium →\rightarrow Teflon.
This orders the substances monotonically from maximum electron mobility to maximum electrical resistance.

Key Concept

Materials are classified into conductors, semiconductors, and insulators based on their atomic structure and ability to permit electron flow.
Estimated Time:1m 0s
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Topics

Conductors, Insulators, and Semiconductors

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