People who contributed to the periodic table

Classification of elements - earliest attempt

1789

Antoine Lavoisier, a French chemist, had attempted to categorise the elements into groups of metals and non-metals.

Classification 2 - Law of triads

1829

Johann Wolfgang Döbereiner arranged the elements into triads based on their chemically similar elements. Döbereiner suggested that the middle element has properties the average of the other two elements in the triad. Hoever, inaccuracy of measurements of the elements (such as atomic weight) at the time hindered classification of more elements.

Classification 3 - Law of octaves

1864

John Newlands proposed his law of octaves, in which elements were arranged into order according to their increasing atomic weights, He also discovered that each element was similar to the elements eight intervals after.

Classification 4 - Mendeleev's law

1869

Dimitiri Mendeleev sorted the elements by their atomic weight in rows, elements with lower atomic masses were on the left.

Trend in periodic table

1869

Lothar Meyer was the earliest person to figure out the trend in the properties of the periodic table. The elements were arranged in the order of their atomic weights and they fell into groups of similar chemical and physical properties repeated at periodic intervals.

Element's identity

1913

Henry Moseley, an English physicist, determined that each element's identity is different, determined by the number of protons present in the atom. This discovery helped his prediction of four new elements, which were later found.