-
Discovery of phosphorous
Before written history, people were aware of some of the elements in the periodic table. Elements such as gold (Au), silver (Ag), copper (Cu), lead (Pb), tin (Sn), and mercury (Hg). It wasn't until 1649, however, until the first element was discovered through scientific inquiry by Hennig Brand . That element was phosphorous (P). -
Period: to
Grouping triads
Between 1817-1829, Johann Dobereiner began to group elements with similar properties in to groups of three or triads. This began in 1817 when he noticed that the atomic weights of strontium, Sr, was halfway between the weights of calcium and barium. These elements possessed similar chemical properties. By 1829, he had discovered the a halogen triad made up of chlorine, bromine, and iodine and a alkali metal triad of lithium, sodium and potassium. He postulated that nature contained triads of ele -
Atomic weight
In 1862, A.E.Beguyer de Chancourtois was the first person to make use of atomic weights to reveal that the elements were arranged according to their atomic weights with similar elements occurring at regular intervals. He drew the elements as a continuous spiral around a cylinder divided into 16 parts. A list of elements was wrapped around a cylinder so that several sets of similar elements lined up, creating the first geometric representation of the periodic law -
Music and chemistry
In 1863, John Newlands, an English chemist, proposed the Law of Octaves which stated that elements repeated their chemical properties every eighth element. The musical analogy was ridiculed at the time, but was found to be insightful after the work of Mendeleev and Meyer were published. -
63 elements
By 1869, 63 elements had been discovered.
