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Revision Notes

Periodic Classification of Elements — Revision Notes

NIOS · Class 10 · Science & Tech

Periodic Classification of Elements revision notes for NIOS Class 10 Science & Tech: 4 topics in quick points.

44 questions40 flashcards4 formulas & key relations5 concepts

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An illustration showing a well-organized chemist's shop with medicines classified and arranged, contrasting it with a disorganized one, to explain the need for classifying elements.
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Key Topics to Revise

1

Development of Classification of Elements

  • The first classification of elements was into metals and non-metals.
  • Germanium and antimony showed properties of both metals and non-metals, so this simple classification was limited.
  • William Prout’s 1815 work showed that the atomic mass of an element remains constant, which became a basis for classification.
2

Dobereiner’s Triads

  • In 1829, J.W. Dobereiner grouped elements into sets of three called triads.
  • The middle element of a triad had an atomic mass nearly equal to the arithmetic mean of the other two.
  • The middle element also had properties intermediate between the other two.
3

Newlands’ Law of Octaves

  • In 1864, John Alexander Newlands arranged elements in increasing order of atomic mass.
  • He observed that every eighth element had properties similar to the first.
  • This was called the Law of Octaves.
4

Mendeleev’s Periodic Law and Periodic Table

  • D’mitri Mendeleev studied 63 known elements and their compounds.
  • In 1869, he stated that the chemical and physical properties of elements are a periodic function of their atomic masses.
  • He arranged elements in increasing order of atomic mass and placed elements with similar properties in the same group.

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Full Notes

Key Concepts

The first classification of elementsWilliam Prout's work in 1815 showedIn 1829In 1864In 1869

Frequently Asked Questions

What are the important topics in Periodic Classification of Elements for NIOS Class 10 Science & Tech?
Key topics in Periodic Classification of Elements include Development of Classification of Elements, Dobereiner’s Triads, Newlands’ Law of Octaves, Mendeleev’s Periodic Law and Periodic Table. Study these first, then practise questions on each for the NIOS Class 10 board exam.
How should I revise Periodic Classification of Elements for the NIOS Class 10 board exam?
Learn the core ideas first, then work through the 44 practice questions on Periodic Classification of Elements. Revise definitions regularly and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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