Periodic table (detailed cells)
Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869. Mendeleev invented the table to illustrate recurring ("periodic") trends in the properties of the elements. The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behavior.
Abū Ishāq Ibrāhīm al-Zarqālī
Al-Zarqālī also contributed to the famous "Tables of Toledo", an adaptation of earlier astronomical data to the location of Toledo along with the addition of some new material. Al-Zarqālī was famous as well for his own "Book of Tables." Many "books of tables" had been compiled, but his almanac contained tables which allowed one to find the days on which the Coptic, Roman, lunar, and Persian months begin, other tables which give the position of planets at any given time, and still others facilitating the prediction of solar and lunar eclipses.