The Periodic Table of Chemical Elements, which was first published by Russian scientist Dmitri Mendeleev on Feb. 17, 1869, is celebrating its 150th anniversary this year.

The Year Of The Period Table

To mark the occasion, the United Nations Educational, Scientific, and Cultural Organization or UNESCO has declared 2019 as the Year of the Periodic Table. The organization called the Periodic Table of Chemical Elements as "one of the most significant achievements in science, capturing the essence not only of chemistry but also of physics and biology."

Festivities officially kicked off on Jan. 29, Tuesday, in Paris. Scientists from all over the world gathered at the UNESCO headquarters for lectures, round table discussions, hands-on chemistry demonstrations, and other activities to celebrate the icon of science.

Also on display in Paris is an 1885 wallchart, which is believed to be the earliest surviving example of the classroom periodic table.

The opening ceremonies held this week is only the beginning of the year-long event to commemorate the periodic table and its significance to the scientific community. The UNESCO says that more events, including competitions, will take place around the world throughout the year.

The Birth And Future Of The Periodic Table

While writing a textbook, Mendeleev, a chemist, spotted an elegant pattern in which certain elements exhibited similar traits and that these traits varied with increasing atomic weight. Thus, in 1869, the periodic table was born with the 60 elements known at the time. He called it "An Attempt at a System of Elements, Based on Their Atomic Weight and Chemical Affinity."

The project, which was initially meant to lighten his work, has persisted and became a staple in every chemistry classroom around the world. The Periodic Table of Elements, 150 years later, has grown to 118 elements, many of which are man-made. The most recent additions were confirmed by the International Union of Pure and Applied Chemistry in December 2015 and were all created inside laboratories.

Michael Gordin, a science historian at Princeton University, said that the Periodic Table of Elements will continue to grow.

"I'm sure somebody will try to create new elements so you could build further rows," he told The Los Angeles Times. "But the question of whether it's worth the investment for the amount of knowledge we get is a question that scientists and politicians would have to answer. It's not my business to decide."