Class 10 Science - TAMILNADU
Periodic Classification of Elements
The chapter Periodic Classification of Elements in Tamil Nadu Samacheer Kalvi Class 10 Science explores how elements are systematically arranged based on their physical and chemical properties. Students will learn the historical development of the periodic table, starting from Dobereiner's triads and Newlands' law of octaves, to Mendeleev's periodic table and the modern periodic table. The chapter covers periodicity in properties such as atomic radius, ionization energy, electron affinity, and electronegativity along periods and groups. Mastering this chapter is crucial for board exams as it forms the foundation of inorganic chemistry and frequently features in objective and descriptive questions.
Start Learning FreeKey Concepts
Modern Periodic Law
The physical and chemical properties of elements are the periodic functions of their atomic numbers.
Groups and Periods
The vertical columns in the periodic table are called groups (1 to 18) and the horizontal rows are called periods (1 to 7).
Atomic Radius
The distance from the center of the nucleus to the outermost shell of electrons; it decreases across a period and increases down a group.
Ionization Energy
The amount of energy required to remove the most loosely bound electron from an isolated gaseous atom; it generally increases across a period.
Electronegativity
The tendency of an atom to attract shared pairs of electrons towards itself in a chemical bond.
Important Formulas
Board Exam Info
This chapter typically carries around 6 to 8 marks in the Tamil Nadu Samacheer Kalvi Class 10 Science board examination. Questions usually include 1-mark objective questions, 2-mark reasoning questions based on periodic trends, and 4-mark descriptive questions explaining Mendeleev's or Modern Periodic tables.
Frequently Asked Questions
Why is the Modern Periodic Table better than Mendeleev's periodic table?
The Modern Periodic Table is based on atomic number rather than atomic mass, which successfully resolves anomalies like the position of isotopes and incorrect order of atomic weights.
How does atomic radius vary down a group and across a period?
Atomic radius increases down a group due to the addition of new shells, and decreases across a period from left to right due to an increase in nuclear charge.
What are valence electrons?
Valence electrons are the electrons present in the outermost shell of an atom, which determine the chemical reactivity and valency of the element.
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