Elements and Compounds

Core concept

Compounds have properties completely different from the elements that form them — for example, hydrogen and oxygen are both gases, but when they chemically combine, they form water, a liquid with entirely different properties. This is a key difference from mixtures, where the combined substances keep their individual properties. Elements are represented by chemical symbols (like H for hydrogen, O for oxygen), while compounds are represented by chemical formulas showing the ratio of elements present (like H₂O for water).