The Periodic Table

Chemistry periodic table

A

Actinium

Aluminum

Americium

Antimony

Argon

Arsenic

Astatine

B

Barium

Berkelium

Beryllium

Bismuth

Bohrium

Boron

Bromine

C

Cadmium

Calcium

Californium

Carbon

Cerium

Cesium

Chlorine

Chromium

Cobalt

Copernicium

Copper

Curium

D

Darmstadtium

Dubnium

Dysprosium

E

Einsteinium

Erbium

Europium

F

Fermium

Flerovium

Fluorine

Francium

G

Gadolinium

Gallium

Germanium

Gold

H

Hafnium

Hassium

Helium

Holmium

Hydrogen

I

Indium

Iodine

Iridium

Iron

K

Krypton

L

Lanthanum

Lawrencium

Lead

Lithium

Livermorium

Lutetium

M

Magnesium

Manganese

Meitnerium

Mendelevium

Mercury

Molybdenum

N

Neodymium

Neon

Neptunium

Nickel

Niobium

Nitrogen

Nobelium

O

Osmium

Oxygen

P

Palladium

Phosphorus

Platinum

Plutonium

Polonium

Potassium

Praseodymium

Promethium

Protactinium

R

Radium

Radon

Rhenium

Rhodium

Roentgenium

Rubidium

Ruthenium

Rutherfordium

S

Samarium

Scandium

Seaborgium

Selenium

Silicon

Silver

Sodium

Strontium

Sulfur

T

Tantalum

Technetium

Tellurium

Terbium

Thallium

Thorium

Thulium

Tin

Titanium

Tungsten

U

Ununoctium

Ununpentium

Ununseptium

Ununtrium

Uranium

V

Vanadium

X

Xenon

Y

Ytterbium

Yttrium

Z

Zinc

Zirconium

Interactive Periodic Table

Alphabetical Element List

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The Periodic Table

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The Discovery and History of the Periodic Table

Author: Dr. Doug Stewart

The periodic table we use today is based on the one devised and published by Dmitri Mendeleev in 1869.

Mendeleev found he could arrange the 65 elements then known in a grid or table so that each element had:

1. A higher atomic weight than the one on its left. For example, magnesium (atomic weight 24.3) is placed to the right of sodium (atomic weight 23.0).

2. Similar chemical properties to other elements in the same column - in other words similar chemical reactions. Magnesium, for example, is placed in the alkali earths' column.

Mendeleev realized that the table in front of him lay at the very heart of chemistry. And more than that, Mendeleev saw that his table was incomplete - there were spaces where elements should be, but no-one had discovered them.

Just as Adams and Le Verrier could be said to have discovered the planet Neptune on paper, Mendeleev could be said to have discovered germanium on paper. He called this new element eka-silicon , after observing a gap in the periodic table between silicon and tin.

Similarly, Mendeleev discovered gallium (eka -aluminum) and scandium (eka -boron) on paper, because he predicted their existence and their properties before their actual discoveries.

Although Mendeleev had made a crucial breakthrough, he made little further progress. With the benefit of hindsight, we know that Mendeleev's periodic table was underpinned by false reasoning. Mendeleev believed, incorrectly, that chemical properties were determined by atomic weight. Of course, this was perfectly reasonable when we consider scientific knowledge in 1869.

In 1869 the electron itself had not been discovered - that didn't happen for another 27 years.

In fact, it took all of 44 years for the correct explanation of the regular patterns in Mendeleev's periodic table to be found...