In 1869, Dmitri Mendeleev published the periodic table. This table is a visual creation of the periodic law. It states the certain properties of elements, arranged by the atomic number. They arranges elements into vertical columns which are also know as groups and horizontal rows which are know as periods.
Here is a worksheet that we did on the periodic tables. We found the elements with the highest and lowest boiling point, melting point, density, atomic radius, electronegatvity and the number of isotopes in each different row.