Historical Development of the Periodic Table

4.1

Development of Periodic Table of Elements

The Periodic Table of Elements

Classifies known chemical elements in a table according to certain characteristics.

Classification of Elements

The chemists try to develop and make a generalisation of the element by classifying it into a certain characteristic.
The classification will enable scientists;
- to generalise the chemical and physical properties.
- to predict the position of an element.
- to identify and compare elements from a different group.
- to predict chemical and physical properties.

Contribution of Scientists to the Development of the Periodic Table

Antoine Lavoisier

Group the element into four groups, which are gas, metal, non-metal and metal oxide.
Light and heat are included in the classification.
Some elements are in the wrong group because of different chemical properties.

Johann W. Dobereiner

Group the elements into three which are called as a triad.
Discovers the relationship between the relative atomic mass (RAM) of the element in each triad.
However, this relationship does not apply to most of the other elements.

John Newlands

Arranged the elements in order of increasing nucleon number.
The chemical properties of every eight elements are similar, and it is known as the law of octaves.
The classification was a failure because of:
- The law of octaves was only accurate for the first 16 elements.
- There was no position allocated for elements yet to be discovered.

Lothar Meyer

Calculated the volume of an atom by dividing the mass with the density of the element.

Dmitri Mendeleev

Arranged the elements in order of increasing atomic mass.
The arrangement followed the atomic mass but not the chemical properties.

Henry G.J. Moseley

Bombarded different elements with high energy electrons and measured the frequency of the X-ray emitted by the element.
Plotted the square root of the frequency of the X-ray against the proton number.
Managed to get a straight line graph.

Basic Principle of Arrangement of Elements in the Periodic Table of Elements

Elements in the Periodic Table of Elements are arranged in ascending order of proton numbers, ranging from 1 to 118.
Elements with similar chemical properties are placed in the same vertical columns

Discovery of New Elements
Element	Symbol	Number of Proton
Nihonium	Nh	113
Moscovium	Mc	115
Tennessine	Ts	117
Oganesson	Og	118

Historical Development of the Periodic Table

4.1

Development of Periodic Table of Elements

The Periodic Table of Elements

Classifies known chemical elements in a table according to certain characteristics.

Classification of Elements

The chemists try to develop and make a generalisation of the element by classifying it into a certain characteristic.
The classification will enable scientists;
- to generalise the chemical and physical properties.
- to predict the position of an element.
- to identify and compare elements from a different group.
- to predict chemical and physical properties.

Contribution of Scientists to the Development of the Periodic Table

Antoine Lavoisier

Group the element into four groups, which are gas, metal, non-metal and metal oxide.
Light and heat are included in the classification.
Some elements are in the wrong group because of different chemical properties.

Johann W. Dobereiner

Group the elements into three which are called as a triad.
Discovers the relationship between the relative atomic mass (RAM) of the element in each triad.
However, this relationship does not apply to most of the other elements.

John Newlands

Arranged the elements in order of increasing nucleon number.
The chemical properties of every eight elements are similar, and it is known as the law of octaves.
The classification was a failure because of:
- The law of octaves was only accurate for the first 16 elements.
- There was no position allocated for elements yet to be discovered.

Lothar Meyer

Calculated the volume of an atom by dividing the mass with the density of the element.

Dmitri Mendeleev

Arranged the elements in order of increasing atomic mass.
The arrangement followed the atomic mass but not the chemical properties.

Henry G.J. Moseley

Bombarded different elements with high energy electrons and measured the frequency of the X-ray emitted by the element.
Plotted the square root of the frequency of the X-ray against the proton number.
Managed to get a straight line graph.

Basic Principle of Arrangement of Elements in the Periodic Table of Elements

Elements in the Periodic Table of Elements are arranged in ascending order of proton numbers, ranging from 1 to 118.
Elements with similar chemical properties are placed in the same vertical columns

Discovery of New Elements
Element	Symbol	Number of Proton
Nihonium	Nh	113
Moscovium	Mc	115
Tennessine	Ts	117
Oganesson	Og	118

Historical Development of the Periodic Table

Historical Development of the Periodic Table

Chapter : Periodic Table of Elements

Topic : Development of Periodic Table of Elements

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