In 1869, Russian chemist Dmitri Mendeleev organized the known elements into the first periodic table by increasing atomic mass from left to right and top to bottom, grouping elements with similar physical and chemical properties. The periodic table shows the atomic number, symbol, atomic mass, and common sources of elements like potassium, gold, and helium.

1. Periodic Table
Sarah McGibbon

2. Where It Came From
✤ In 1869, Russian chemist, Dmitri
Mendeleev, came up with a way to
organize the elements that had been
discovered at that time.

3. Organization
✤ Mendeleev organized it by increasing atomic mass, the farther
down and to the right the element is, the higher the atomic mass is.
He then grouped them into groups or families, based on their
physical and chemical properties.

4. Elements Relationships
✤ The closer the elements are
together, the closer they are in
atomic mass, number and
material

5. Potassium
✤ Atomic Number: 19
✤ Symbol: K
✤ Atomic Mass: 39.0983
✤ Potassium is found in bananas, milk and some
meats

6. Gold
✤ Atomic number: 79
✤ Symbol: Au
✤ Atomic Mass: 196.966569
✤ Gold is found in things such as jewelry, old
antiques and gold bars

7. Helium
✤ Atomic Number: 2
✤ Symbol: He
✤ Atomic Mass: 4.002602
✤ Helium is found in things such as balloons,
cooling agents for nuclear reactors and
supersonic wind tunnels

8. Sources
✤ "Origin of the Periodic Table." Origin of the Periodic Table. N.p., n.d. Web. 25 Oct. 2012.
<http://www.colorado.edu/physics/2000/periodic_table/index.html>.
✤ "Dynamic Periodic Table." Dynamic Periodic Table. N.p., n.d. Web. 25 Oct. 2012. <http://
ptable.com/>.