Glenn Seaborg discovered the transuranium elements from 94 to 102 in the mid-20th century and reconfigured the periodic table by placing the actinide series below the lanthanide series. He was awarded the 1951 Nobel Prize in Chemistry for his work, and element 106 was named seaborgium in his honor. The modern periodic table arranges elements in order of increasing atomic number, with rows called periods and columns called groups.

1. Periodic Table

2. Dmitri Mendeleev and the
Periodic Table
• Mendeleev was the first to
publish a version of the table
that we could recognize today.
• He was very fond of solitare
card game, which inspired him
to create the periodic table.
• In 1869, he created a card for
each of the 63 known elements
and arranged them into a
periodic table according to their
chemical properties and atomic
masses.

3. Mendeleev’s Periodic Table

4. The Modern Periodic Table
The last major changes to the modern periodic table
resulted from Glenn Seaborg's work in the middle
of the 20th Century. He discovered the transuranium
elements from 94 to 102 and reconfigured the
periodic table by placing the actinide series below
the lanthanide series. In 1951, Seaborg was awarded
the Nobel Prize in chemistry for his work. Element
106 has been named seaborgium (Sg) in his honor.
The modern periodic table lists the elements in order
of increasing atomic number (the number of protons
in the nucleus of an atom), in which the rows of the
table are called periods and the columns are called
groups.

5. The Modern Periodic Table