PRESENTATION OUTLINE
Johann Doberneir In 1829, he classified some elements into three groups, called the triads. The elements in a triad had similar chemical properties and orderly physical properties.
John Newlands suggested that elements be arranged in octaves because he noticed after arranging the elements in order of increasing atomic mass that certain properties repeated the 8th element (idea failed)
Dmitri Mendeleev In 1869 published a table of the elements organized by increasing atomic mass
Sir William Ramsay was a Scottish chemist who discovered the noble gases and received the Nobel Prize in Chemistry in 1904 "in recognition of his services in the discovery of the inert gaseous elements in air".
In 1913, through his x-rays he determined the actual nuclear charge(atomic #) of the elements. He rearranged the elements in order of increasing atomic number
He was called as the "Father of Modern Chemistry"
