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Chapter 6 of 32
Syllabus

Periodic Classification of Elements

NIOS · Class 10 · Science & Tech

Complete topic list for Periodic Classification of Elements in NIOS Class 10 Science & Tech. Key concepts, sub-topics, and what to focus on for board exams.

44 questions40 flashcards5 concepts

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4 Topics · NIOS Class 10 Science & Tech

Topics in Periodic Classification of Elements

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.

Key Concepts

Central concept: Periodic classification of elements based on atomic mass and atomic number, showing the development from early classifications to the modern periodic table

Need for classificationEarly classificationsDobereiner's triadsNewlands' law of octavesMendeleev's periodic tableDefects of Mendeleev's tableModern periodic lawModern periodic table

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 Periodic Classification Development Overview, Periodic Classification Overview, Periodic Classification Overview. These are the concepts NIOS Class 10 examiners draw on most — study them first, then practise related questions.
How to score full marks in Periodic Classification of Elements — NIOS Class 10 Science & Tech?
Understand the core concepts first, then work through the 44 practice questions available for this chapter. Revise formulas and 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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