-
he classified some elements into groups of three, which he called triads
-
he suggested that elements be arranged in “octaves” because he noticed (after arranging the elements in order of increasing atomic mass) that certain properties repeated every 8th element.
-
At the same time, he published his own table of the elements organized by increasing atomic mass.
-
he published a table of the elements organized by increasing atomic mass.
-
through his work with X-rays, he determined the actual nuclear charge (atomic number) of the elements*. He rearranged the elements in order of increasing atomic number.
-
After co-discovering 10 new elements, in 1944 he moved 14 elements out of the main body of the periodic table to their current location below the Lanthanide series. These became knownas the Actinide series.