Dmitri Mendeleev is widely credited as the creator of the periodic table. A charismatic Russian scientist who was fascinated by chemistry, Mendeleev came up with the idea to organize chemical elements according to their atomic number and other properties. The first periodic table was published by Mendeleev in 1869.
The first periodic table only consisted of elements known at the time. It has since been expanded to include 118 elements and may still grow. It is typically laid out in a grid of 18 columns and seven rows, with a double-row block below that. The rows of the table are called periods.