How the periodic table came to be Today’s Video of the Day comes from the American Chemical Society’s Reactions series and features a brief history of the periodic table.
Most people probably don’t remember a time when the periodic table wasn’t proudly displayed in all science classrooms, but the truth is that the key science chart took many years to develop.
Now, the finished product displays the chemical elements arranged by atomic number, electron configuration, and chemical properties, paving the way for chemistry breakthroughs for years to come. The Russian chemist Dmitri Mendeleev was the first scientist to make a periodic table similar to the one used today. Mendeleev arranged the elements by atomic mass, corresponding to relative molar mass.
The reason the periodic table is the shape that it is has to do with the electronic configurations of the elements. It ia arranged so that all the elements in each period (row) have similar electronic configurations to the other elements in that period. There are 118 known elements. Actinide Metals: A series of radioactive metallic elements in Group 3 of the periodic table. Orbital: A region of space surrounding an atom’s nucleus where an electron is likely to be found.
Video Credit: American Chemical Society