Periodic Classification of Elements — Class 10 Science MCQs

NCERT | CBSE Curriculum

Practice 100+ MCQs on Periodic Classification of Elements for Class 10.
Mendeleev's table, modern periodic law, periods, groups, atomic size & electronegativity trends.
Instant answers & performance report.

Score:
0
Time:
05:00

Quick Revision: Periodic Classification of Elements

  • Dobereiner's Triads (1817): Groups of 3 elements where middle element's atomic mass ≈ average of other two (e.g., Li, Na, K).
  • Newlands' Law of Octaves (1866): Every 8th element has properties similar to 1st, like musical notes.
  • Mendeleev's Periodic Table (1869): Arranged elements by atomic mass; left gaps for undiscovered elements.
  • Mendeleev's Periodic Law: Properties are periodic functions of atomic masses.
  • Modern Periodic Law (Moseley, 1913): Properties are periodic functions of atomic numbers.
  • Modern Periodic Table: 18 Groups (vertical), 7 Periods (horizontal); based on atomic number.
  • Groups: Vertical columns (1-18); elements have same valence electrons → similar chemical properties.
  • Periods: Horizontal rows (1-7); elements have same number of electron shells.
  • Atomic Size Trend: Decreases across period (← to →), increases down group (↑ to ↓).
  • Metallic Character: Decreases across period, increases down group.
  • Non-Metallic Character: Increases across period, decreases down group.
  • Ionization Energy: Energy to remove electron; increases across period, decreases down group.
  • Electronegativity: Atom's electron-attracting ability; increases across period, decreases down group.
  • Valency: Group 1-2: same as group number; Group 13-18: (18 - group number) for non-metals.
  • Group 1: Alkali metals (Li, Na, K...); 1 valence electron; highly reactive; form basic oxides.
  • Group 2: Alkaline earth metals (Be, Mg, Ca...); 2 valence electrons.
  • Group 17: Halogens (F, Cl, Br...); 7 valence electrons; highly reactive non-metals.
  • Group 18: Noble gases (He, Ne, Ar...); complete valence shells; inert; valency = 0.
  • Oxide Nature: Metals → basic oxides; Non-metals → acidic oxides; Metalloids → amphoteric oxides.
  • Blocks: s-block (Groups 1-2), p-block (Groups 13-18), d-block (transition metals), f-block (lanthanides/actinides).

External Resources: Byjus - Periodic Classification | Khan Academy - Periodic Table

Chapter Summary: Periodic Classification of Elements

Periodic Classification of Elements MCQ Class 10 takes you through the fascinating journey of how scientists gradually discovered patterns in elemental properties. We start with Dobereiner's triads and Newlands' Law of Octaves, then study Mendeleev's Periodic Table which arranged elements by atomic mass and left gaps for undiscovered elements.

We then explore the Modern Periodic Table based on atomic number, with 18 groups and 7 periods. We learn about periodic trends like atomic size, metallic character, ionization energy, and electronegativity. Understanding these trends helps predict element properties and explains why elements in the same group show similar chemical behavior.

This chapter is crucial for board exams with questions on historical developments, group names, positions of elements, and periodic trends. Regular practice helps you quickly locate elements, predict properties, and explain trends—turning the periodic table from a daunting chart into your most reliable scoring tool in chemistry exams.