PERIODIC TABLEGenesis of Periodic Classification of Elements!

STEPWISE DEVELOPMENT OF PERIODIC TABLE

Dobereiner’s Law of TriadsNewland’s Law of OctavesMendeleev’s Old Periodic Law

Moseley’s Modern Periodic Law

DOBEREINER’S LAW OF TRIADS In each group of three members called triads, the middle

element had an atomic weight about half way between the atomic weights of the other two

NEWLAND’S LAW OF OCTAVES

The arrangement of the elements in increasing order of their atomic weights and noted that every eighth element had properties similar to the first element

The relationship was just like every eighth note that resembles the first in octaves of music.

NEWLAND’S TABLE

This study awarded Davy medal

MENDELEEV’S OLD PERIODIC LAW

Mendeleev’s Law (Old periodic law) states that “The properties of the elements are a periodic function of their atomic weights”

Mendeleev predicted the existence and properties of some elements and his prediction was absolutely correct

He called the groups as “columns” and periods as “series”

MOSELEY’S MODERN PERIODIC LAW

Modern Periodic Law states that “The properties of the elements are a periodic function of their atomic numbers”

He said that the properties of every elements varies with atomic number not with atomic mass

The modern periodic table is in accordance with modern periodic law

LONG FORM OF PERIODIC TABLE Periodic table consists of seven periods numbered

from 1 to 7 and the 7th period is still incomplete Periodic table consists of eighteen groups

numbered from 1 to 18 Pure metals are placed on left hand side and non

metals on the right hand side Hydrogen finds a separate and unique position in

the periodic table because its property does not match with any other elements

Periodic table is divided into four main blocks depending upon where the last electron enters namely s-, p-, d- or f-blocks

The liquid metal present in periodic table is mercury (Hg) and the liquid non metal is bromine (Br)

LATIN NAME FOR SOME ELEMENTS

Sodium – Natrium (Na)Potassium – Kalium (K)

Mercury – Hydrargyrum (Hg)Silver – Argentum (Ag)

Gold – Aurum (Au)Tin – Stannum (Sn)

Lead – Plumbum (Pb)

THE END!

PRESENTED BYNITHYA S

NAIRPhysical ScienceBadriya CollegeVelichakkalaKollam

THANK YOU