History of the Periodic table
- Until quite recently, there were only two ways to categorize elements: by physical or chemical properties or by their relative atomic mass.
- In the 1800s, no one knew about atomic structure or protons and electrons, so people didn't know about atomic numbers.
- The known elements were therefore arranged by atomic mass. When this was done, a periodic pattern was noticed in the properties of elements.
- Newlands was the first to to try to arrange things in a better way in 1864. He noticed that every eighth element had…