Periodic Classification of Elements

State Council of Educational Research and Training, Tamil Nadu (2020) Periodic Classification of Elements. [Teaching/Learning Resource]

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We live in the world of substances with great diversity. Substances are formed by the combination of various elements. All the elements are unique in their nature and property. To categorize these elements according to their properties, scientists started to look for a way. In 1800, there were only 31 known elements. By 1865, their number became 63. Now 118 elements have been discovered. As different elements were being discovered, scientists gathered more and more information about the properties of these elements. They found it difficult to organize all that was known about the elements. They started looking for some pattern in their properties, on the basis of which they could study such a large number of elements with ease. Let us discuss the concepts of classification of elements proposed by various scientists from early to modern period.

Item Type: Teaching/Learning Resource
Program: A publication under Free Textbook Programme of Government of Tamil Nadu
Learning outcomes: After completing this lesson, students will be able to � know the concept of classification of elements in early days. � understand the postulates, advantages and limitations of modern periodic table. � understand the classification of elements based on the electronic configuration. � learn about the position of hydrogen in the periodic table. � study about the position of rare gases (Noble gases) in the periodic table. � distinguish between metals and non-metals. � know about metalloids and alloys.
Access: Open
Uncontrolled Keywords: Chemistry; Elements
Subjects: Science General
Curriculam Level: 4. Junior Secondary
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Depositing User: COL Staff
Date Deposited: 11 Apr 2021 08:03
Last Modified: 22 Apr 2021 00:47

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