The Most Abundant Elements by Mass

In Human Body
65% Oxygen
18% Carbon
10% Hydrogen

At Earth's Surface
49% Oxygen
26% Silcon

In the Universe
74% Hydrogen
24% Helium

Dimitri Mendeleev
Play around with this interactive Periodic Table to learn about the timing of the discovery of the elements.
Another very interesting, interactive Periodic Table.
A Periodic Table loaded with information about each element.
A very visual Periodic Table also loaded with information.
One more amazing Periodic Table - suggested by Eliana Zimmerman
One more interactive Periodic Table.
A website that lists the atomic radii of each element
A website that lists ionization energies of each element.
A wiki page developed by a past NHS student about various “scientists of olde”
Dimitri Mendeleev was a Russian Chemistry Teacher who was searching for a way to help his students categorize the elements to better remember them. In 1869 he published his first periodic table in his chemistry textbook. He arranged the elements in specific horizontal rows and vertical columns according to their physical properties and in order of increasing mass. Later they were slightly rearranged by increasing atomic number. Since all the elements had not yet been discovered, Mendeleev had the good sense to leave spaces in his chart and even predicted the masses of elements that would later fit into those "holes."
Just how did all those elements get their names??? Scroll down this website to find out.

Ernest Rutherford
For this his work naming the proton, alpha particles, and beta particles, Rutherford won the 1908 Nobel Prize in chemistry.

In 1909, at the University of Manchester in England, Rutherford was bombarding a thin gold foil with positively charged alpha particles when he noticed that although almost all of them went through the gold, one in eight thousand would "bounce" (i.e., scatter) back, indicating the presence of solid matter. Rutherford's work showed that atoms consisted primarily of empty space surrounding a well-defined central core called a nucleus. The amazed Rutherford commented that it was "as if you fired a 15-inch naval shell at a piece of tissue paper and the shell came right back and hit you."
This experiment was used by Rutherford in the 1910's to verify the existence of the very dense nucleus. The chocolate chip cookie model would not have explained the deflection of the alpha particles that deflected directly back towards the alpha source.

John Dalton
It was gentle John Dalton who finally sorted out the rumblings of late 18th-century chemists and gave us a proper atomic theory. Dalton lived a quiet life of modest means. He was a bachelor and a devout Quaker who showed little passion of any kind. One subject did elicit a flare of anger, though. That was the debate over what symbols to use to represent atoms
Dalton spent his life licking the wounds of an early failed love. He did very little lab work as he was not a very good experimentalist, although an excellent theorist. He tutored students for money and spend much time studying and formulating his theories. His only pastime was lawn bowling, and that becomes part of this story. His friends described him as awkward, strident, without social grace, and admirably independent.
In 1802, when he was 36, he began forming and setting forth his atomic theory of matter. He showed how matter is made of elemental atoms, and that atoms of each material have a distinct weight. Although he didn't have the weights quite right, he clearly saw that when elements combine, they have to do so in fixed proportions.
Dalton used round circles to identify the atoms. His phosphorus looked like a Mercedes hood ornament. Oxygen was an empty circle, and hydrogen had a dot in the middle. For water, which he thought was HO, he used two circles, one with a dot in the middle and one open. Dalton argued strenuously against our modern notation. There had been a debate raging among scientists. Should they make grand theories about nature, or do they just report the facts, carefully and accurately? Atoms were an ancient theoretical idea from Democritus' time. But the prevailing mood in 1802 was to take Dalton's theoretical atoms as only a metaphor for rules of chemical combination. Many scientists still believed they weren't real. But Dalton loved lawn bowling, and his atoms were as real to him as those wooden bowling balls which made him shy away from the more modern symbolic method of representing the atoms that elements are made of.