Question T5A07
From subelement T5 - T5A
Why are metals generally good conductors of electricity?
Why is this correct?
Metals are excellent conductors because they have many free electrons that can move easily through the material. These mobile electrons create a pathway for electrical current to flow. High density (choice A) doesn't determine conductivity - lead is dense but not as conductive as copper. Free protons (choice C) don't exist in metals; protons are bound in atomic nuclei and cannot move freely to carry current.
Memory tip
Remember the key pattern: conductivity depends on mobile charge carriers, not physical properties like density or weight. When evaluating materials, always ask 'what can move freely to carry current?' In metals, it's always electrons, never protons.
Learn more
In practical amateur radio construction, this principle explains why we use copper wire for antenna elements and feed lines, while aluminum is acceptable for larger structures despite being lighter. The abundance of free electrons in both metals enables efficient RF current flow. Understanding electron mobility also helps explain why oxidation degrades connections - it creates barriers that impede free electron movement, increasing resistance and reducing signal quality.
Think about it
Why do you think silver-plated connectors are used in high-frequency applications even though copper alone conducts electricity well?