University of Nottingham’s chemistry professor Martyn Poliakoff says that most chemists don’t know the atomic number of most elements and that it’s a pain to look in the periodic table. That’s why ...

The periodic table of elements—also known as Mendeleev’s table—was developed in 1869 by Russian chemist Dmitri Mendeleev. It organizes all known chemical elements by their atomic number, which is the ...

Editor’s note: The following, originally published with the title “Putting the Elements in Their Places,” is the introduction to the Scientific American Classics special digital edition,“The Quest for ...

Electrons in atoms occupy energy levels, also called electron shells, outside the nucleus. Different shells can hold different maximum numbers of electrons. The electrons in an atom occupy the lowest ...

The modern periodic table, arranged in rows and columns, was first introduced by Dmitri Mendeleev in 1869. At the time, it included the known elements and their properties, but Mendeleev predicted ...

Play this game to learn about lots of different elements in the periodic table. While you're watching, look out for where different elements are found in the periodic table. Mrs Roberts: So, here I ...