Peridic Table

Periodic Table

First noticed by Greek people in about 400BC. They used the words

"element", and "atom" to describe the differences and smallest parts of

matter. Those ideas lasted for 2000 years. Elements were Earth, Fire, Air,

and Water that explained "world stuff" easily came and went.

In the 1600's Boyle, an experimenter, influenced by Democritus,

Gassendi, and Descartes lent important weight to the atomic theory of

matter. In the 1700's Lavoisier divided the elements into four classes.

John Dalton suggested that the mass of an atom is the important property.

"The chemical elements are composed of... indivisible particles of

matter, called atoms... atoms of the same element are identical in all

respects, particularly weight."

n the 1800's Doereiner said that some elements had a relative atomic

mass, and DeChancourtois made a table of elements to show the periodic

reoccurrence of properties. In the 1860's Newland made a table of

elements giving them a serial number in order of their atomic weighs

starting with Hydrogen.

Meyer and Mendeleyev made periodic tables independently. Meyer

made it more periodicity of physical properties, and Mendeleyev made it

more on the chemical properties. Mendeleyev published his periodic table

& law in 1869. Periodic tables have always been related to how scientists

thought about the shape and structure of the atom. Later, the table was

reordered by Mosely according to atomic numbers(nuclear charge) instead

of weight.

Harry D. Hubbard, of the United States