History and arrangement of the periodic table

Today you will be learning about the history and arrangement of the period table. The periodic table organizes all the elements in columns and periods. The horizontal rows are called periods and the vertical columns are called groups. 

How did the work of Dmitri Mendeleev differ from that of John Newlands in the development of the periodic table?

Who is credited with creating the first periodic table?

Which is another name for groups of elements?

Which element has the greatest average atomic mass?

In 1869 Russian chemist Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements and left spaces open in his periodic table for them. In 1886 French physicist Antoine Bequerel first discovered radioactivity. British chemist John Newlands was the first to arrange the elements into a periodic table with increasing order of atomic masses. He found that every eight elements had similar properties and called this the law of octaves. He arranged the elements in eight groups but left no gaps for undiscovered elements. 

In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom. The periodic table has long-since filled in Mendeleev's gaps and has added new elements. It has even changed the weights of other elements. The periodic table is continually being changed as new discoveries are made and new theories are developed to explain the behavior of chemicals.

   This is some information of the history and arrangement of the periodic table.