This is made of aluminium ... Mrs Roberts: Well, the modern periodic table shows us all of the elements arranged in rows, which are called periods. It has changed a lot over the years as we ...

In 1843, Leopold Gmelin worked with the Dobereiner’s system and developed a table of 55 elements that contained many of the similar relationships later found in the modern periodic ... discovered the ...

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 ...