The Periodic Table of Chemical Elements is one of the most significant achievements in science, capturing the essence not only of chemistry, but also of physics and biology. It is the common language of science!
1869 is considered as the year of discovery of the Periodic System by Dmitri Mendeleev, who discovered the Periodic Law on March 1, 1869.
Actually, Dmitri Mendeleev and Lothar Meyer individually came up with the periodic law, which states that “when the elements are arranged in order of increasing atomic mass, certain sets of properties recur periodically.” Meyer based his laws on the atomic volume (the atomic mass of an element divided by the density of its solid form), this property is called Molar volume.
Mendeleev created the first periodic table and was shortly followed by Meyer. Mendeleev’s table is noteworthy because it exhibits mostly accurate values for atomic mass and it also contains blank spaces for unknown elements.
Mendeleev’s periodic table is an arrangement of the elements that group similar elements together. He left blank spaces for the undiscovered elements (atomic masses, element: 44, scandium; 68, gallium; 72, germanium; & 100, technetium) so that certain elements can be grouped together. However, Mendeleev had not predicted the noble gases, so no spots were left for them.
Figure 1. Mendeleev’s original periodic table
Figure 2. Recent edition of the periodic table by the International Union of Pure and Applied Chemistry (IUPAC). Look how much we have progressed since!
2019 will be the 150th anniversary of the Periodic Table of Chemical Elements and has therefore been proclaimed the “International Year of the Periodic Table of Chemical Elements (IYPT2019)” by the United Nations General Assembly and UNESCO. See the official IYPT website for more information.
The International Year aims to recognize the importance of the Periodic Table of Chemical Elements as one of the most important and influential achievements in modern science reflecting the essence not only of chemistry, but also of physics, biology and other basic sciences disciplines.
The IYPT 2019 is an opportunity to reflect upon many aspects of the periodic table, including its history, the role of women in research, global trends and perspectives on science for sustainable development, and the social and economic impacts of this field.
How much do you know about the periodic table? Challenge yourself to the Periodic Table Challenge hosted by IUPAC to celebrate the International Year of the Periodic Table, and for a chance to win a periodic table signed by a Nobel laureate in chemistry!
If you need a refresher from high school chemistry, here is the periodic table song: