Argon is an inert gas in group VIII A of the periodic table with atomic number 18, an atomic weight of 39.948, and a density of 1.40 Mg/m 3. In the solid state it forms an fcc crystal with a melting ...

Just four years before Mendeleev announced his periodic table, Newlands noticed that there were similarities between elements with atomic weights that differed by seven. He called this The Law of ...

Watch this video to find out more information on the periodic table close periodic tableA table which lists all of the chemical elements and arranges them in a way that is useful. It allows us to ...

In 1869, Mendeleev's first periodic table did not include them, as closed-shell elements remained undiscovered until Lord Rayleigh and William Ramsey isolated argon in 1894. Remarkably ...