The Periodic Table, first compiled by Russian chemist Dmitri Mendeleyev,
is organized by the number of protons in the nucleus of each element's atom,
known as the atomic number. The elements are then arranged in order of
increasing atomic numbers. Hydrogen (H), for example, only has one proton, and
is located at the top of the table, while lead (Pb) has 82 protons, and is
located much lower in the table.
What do the colors mean?
The colors in this table are organized by the families to which each
element belongs (see below).
What are families?
Each element in the Periodic Table has distinct properties. To further
organize the table, elements with similar properties are grouped into families.
The major families are: