Before the Table

For most of history, people believed everything was made of four elements: earth, water, air, and fire. The ancient Greeks were confident about this.

By the early 1800s, chemists had identified around 30 elements but had no system for organizing them. They knew hydrogen was light and gold was heavy, but they could not explain why certain elements behaved similarly. It was like having a pile of puzzle pieces with no picture on the box.