History of the Modern History of the Modern Periodic TablePeriodic Table

Before written history…Before written history…

people were aware of some of people were aware of some of the elements in the periodic the elements in the periodic table liketable like gold (Au)gold (Au) silver (Ag)silver (Ag) copper (Cu)copper (Cu) lead (Pb)lead (Pb) tin (Sn)tin (Sn) mercury (Hg)mercury (Hg)

Hennig BrandHennig Brand (1649) (1649)

German alchemistGerman alchemist Discovered the element Discovered the element

phosphorus (P) through phosphorus (P) through scientific inquiry scientific inquiry

Antoine LavoisierAntoine Lavoisier (1789) (1789)

French chemist-physicistFrench chemist-physicist Arranged the elements into Arranged the elements into

groups of simple substances groups of simple substances which will not decompose by which will not decompose by any means any means

John DaltonJohn Dalton (1808-1827) (1808-1827)

English chemist-physicistEnglish chemist-physicist Published his Published his New System of New System of

Chemical Philosophy Chemical Philosophy wherein wherein he calculated the first relative he calculated the first relative masses of atoms and masses of atoms and compounds compounds

John Dalton’s Chart of John Dalton’s Chart of ElementsElements

Jacob BerzeliusJacob Berzelius (1828) (1828)

Swedish chemistSwedish chemist improved the work of Dalton and improved the work of Dalton and

published a table of atomic published a table of atomic weights with 32 elementsweights with 32 elements

Johann DobereinerJohann Dobereiner (1817-1829)(1817-1829)

German chemist German chemist proposes the proposes the Law of Triads Law of Triads in in

arranging the periodic table arranging the periodic table

he noticed that the atomic mass he noticed that the atomic mass of strontium (87.62g) was of strontium (87.62g) was halfway between the masses of halfway between the masses of calcium (40.08g) and barium calcium (40.08g) and barium (137.33g)(137.33g)

These elements possessed These elements possessed similar chemical properties similar chemical properties

Leopold GmelinLeopold Gmelin (1843) (1843)

German chemistGerman chemist published published Handbook der Handbook der

ChemieChemie

his book contains three tetrads his book contains three tetrads and even a pentad - nitrogen, and even a pentad - nitrogen, phosphorus, arsenic, antimony phosphorus, arsenic, antimony and bismuth - which we now and bismuth - which we now recognize as group VA of the p-recognize as group VA of the p-block of the periodic tableblock of the periodic table

Stanislao Cannizzaro Stanislao Cannizzaro (1858)(1858)

Italian chemistItalian chemist settled one essential property

common to all in classifying elements, their atomic mass

Beguyer De ChancourtoisBeguyer De Chancourtois (1862 )(1862 )

French geologist French geologist arranged the elements by arranged the elements by

increasing atomic massesincreasing atomic masses

he placed his arrangement in a he placed his arrangement in a cylinder and divided it into 16 cylinder and divided it into 16 parts, which was based on the parts, which was based on the atomic mass of oxygen. atomic mass of oxygen.

he called this as he called this as telluric screwtelluric screw it was the first ever geometric it was the first ever geometric

representation of the periodic representation of the periodic law law

John NewlandsJohn Newlands (1863) (1863)

English chemist English chemist proposed the proposed the Law of Octaves Law of Octaves in in

arranging the periodic table. arranging the periodic table.

he noticed that when the first 20 he noticed that when the first 20 elements were arranged in elements were arranged in increasing atomic masses, there increasing atomic masses, there will be similarities in the will be similarities in the properties of the first and the properties of the first and the eighth element in the periodeighth element in the period

but this law was no longer but this law was no longer applicable after the element applicable after the element calcium. calcium.

Lothar MeyerLothar Meyer (1869) (1869)

German chemistGerman chemist published a periodic table based

from the idea that properties of elements are periodic function of their atomic masses

Dmitri MendeleevDmitri Mendeleev (1869) (1869)

Russian chemistRussian chemist published a periodic table based

from the idea that properties of elements are periodic function of their atomic masses

Classical Periodic LawClassical Periodic Law

Properties of elements are Properties of elements are periodic function of their atomic periodic function of their atomic masses. masses.

the periodic table of Meyer and the periodic table of Meyer and Mendeleev has vacant elements Mendeleev has vacant elements which are yet to be discovered but which are yet to be discovered but Mendeleev had already predicted Mendeleev had already predicted some physical properties of these some physical properties of these missing elements missing elements

one good example of this is the one good example of this is the missing element between silicon missing element between silicon and tin, he predicted that the and tin, he predicted that the property of this missing element will property of this missing element will be midway between silicon and tin be midway between silicon and tin so he named this as so he named this as eka-silicon.eka-silicon.

Clemens WinklerClemens Winkler (1886) (1886)

German chemistGerman chemist discovered discovered germanium, germanium, an an

element which actually matches element which actually matches the prediction of Mendeleev, the prediction of Mendeleev, eka-siliconeka-silicon

Henry Moseley Henry Moseley (1913) (1913)

English physicist English physicist noticed a connection noticed a connection

between the atomic between the atomic number of an element and number of an element and the frequency of X-rays the frequency of X-rays resulting from the resulting from the bombardment of an bombardment of an element with a high element with a high

energy electron. energy electron.

he found out that atomic number he found out that atomic number increases in the same manner increases in the same manner as the atomic masses with some as the atomic masses with some few exemptions few exemptions

Modern Periodic LawModern Periodic Law

Properties of elements are Properties of elements are periodic function of their atomic periodic function of their atomic numbers. numbers.

Glenn SeaborgGlenn Seaborg (1951) (1951)

American chemist American chemist discovered the transuranium discovered the transuranium

elements with atomic numbers elements with atomic numbers 94-102. 94-102.

the completion of the actinide the completion of the actinide series allows Seaborg to redesign series allows Seaborg to redesign the periodic table into it current the periodic table into it current form form

both the lanthanide and actinide both the lanthanide and actinide series of elements were placed series of elements were placed under the rest of the periodic table, under the rest of the periodic table, these elements technically should these elements technically should be placed between the alkaline be placed between the alkaline earth metals and the transition earth metals and the transition metals; however, since this would metals; however, since this would make the periodic table too wide, make the periodic table too wide, they were placed below the rest of they were placed below the rest of the elements. the elements.

Modern Periodic Table of ElementsModern Periodic Table of Elements

Philip Stewart’sPhilip Stewart’s

Spiral form of the Periodic TableSpiral form of the Periodic Table

Circular Form of the Periodic Circular Form of the Periodic TableTable

The periodic spiral of Prof. Theodore BenfeyThe periodic spiral of Prof. Theodore Benfey

Dr. Timothy Stowe’s Physicists Periodic TableDr. Timothy Stowe’s Physicists Periodic Table

A triangular long-form Periodic Table by Emil A triangular long-form Periodic Table by Emil ZmaczynskiZmaczynski