printable periodic table of elements with key

This is a group of elements such as helium that don’t like to react with other elements. These include the noble gases, identified in 1890. The periodic table continued to grow as scientists discovered more elements. Other scientists were working on their own periodic tables, but Mendeleev published his table first. He saw trends in the elements’ properties that varied over specific intervals, or periods. In 1869, the Russian chemist Dimitri Mendeleev lined up the 63 known elements in order by their atomic weights. An atomic weight is the average weight of one atom of an element. But they did understand that elements had different atomic weights. Back then, scientists didn’t know about the protons, neutrons and electrons that make up atoms. It also shows how its electrons are arranged.ĭuring the mid-1800s, many chemists looked for patterns that explained how elements interacted. An element’s place also shows how likely it is to react. Those on top of the chart have the fewest protons. First, the elements are organized by atomic number, or how many protons they have. The location of each square in the table tells many things about each element. A square contains one or two letters that stand for the element’s name, and numbers that tell about that element’s properties. The table is made up of over a hundred squares.

This is a chart that shows all the known chemical elements. Periodic table (noun, “peer-ee-AHH-dik TAY-bul”)

Printable periodic table of elements with key