Why is copper a good conductor but sulfur isn't?

Copper is a good conductor because it has free electrons that can move easily, while sulfur lacks these free electrons.

Copper is a metal, and like most metals, it has a unique atomic structure that makes it an excellent conductor of electricity. The outermost shell of a copper atom contains just one electron. This electron is not tightly bound to the nucleus, so it can move freely. When an electric field is applied, these free electrons can move easily through the copper, conducting the electric current. This is why copper is often used in electrical wiring and other applications where efficient conduction of electricity is required.

On the other hand, sulfur is a non-metal. Its atomic structure is quite different from that of copper. Sulfur atoms have six electrons in their outermost shell, and these electrons are tightly bound to the nucleus. This means that they cannot move freely, and so sulfur is not a good conductor of electricity. When an electric field is applied, the electrons in sulfur do not move easily, and so the electric current is not conducted efficiently.

Furthermore, the crystalline structure of metals like copper also contributes to their conductivity. In a metal crystal, the atoms are arranged in a regular, repeating pattern. This allows the free electrons to move easily through the crystal, further enhancing the metal's conductivity. In contrast, the crystalline structure of non-metals like sulfur does not facilitate the easy movement of electrons.

In summary, the good conductivity of copper is due to its atomic structure, which allows for the easy movement of free electrons, and its crystalline structure, which further facilitates this movement. Sulfur, on the other hand, lacks these properties, making it a poor conductor of electricity.