What is a characteristic of metals that distinguishes them from non-metals?

A characteristic that distinguishes metals from non-metals is their shiny appearance. Metals, such as iron, aluminum, and gold, have a reflective surface that gives them a lustrous look, which is a result of how they interact with light. This shininess is due to the presence of free-moving electrons in metals that can absorb and re-emit light.

Non-metals, on the other hand, typically lack this shiny quality and often have dull appearances. Non-metals can be found in various physical states at room temperature, including solids (like sulfur and phosphorus), liquids (like bromine), and gases (like oxygen and nitrogen), which contrasts with the solid, reflective nature of most metals.

Understanding the distinctive properties of metals, such as their shininess, helps in identifying and categorizing elements based on their physical and chemical characteristics in the periodic table.