Scientists Development of the Periodic Table

Johann Dobereiner

element triad, groups of three elements with similar properties, and in each case the second element has an atomic mass of about halfway between those of the first and third.

Jar Newlands

law of octaves - arranged known elements by increasing atomic mass along horizontal rows 7 elements long and said that the 8th element would be similar to the first

Dmitri Mendelev

• makes the periodic table but leaves spaces in the table for elements that hadn’t been discovered

• creation of periodic table

Lothar Meyer

also made periodic table, introduced valence property

Mosely

ordering elements according to atomic number instead of atomic mass

Seaborg

• discovered transsuranium elements

• reconfigured the periodic table by placing actinide series below the lanthanide series

Mendeleev’s Periodic Law

properties of the elements are a periodic function of atomic mass

Why Mendeleev given credit?

• Accurate property prediction of yet undiscovered elements

• His table allowed for and was capable of adjusting to future discoveries