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Periodic Classification of Elements — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10SciencePeriodic Classification of Elements5 Marks
Question
Find the valency of first twenty elements.
✓

Answer

The valency of first 20 elements is as follows:
  1. Hydrogen(H) = 1
  2. Helium(He) = 0
  3. Lithium(Li) = 1
  4. Beryllium(Be) = 2
  5. Boron(B) = 3
  6. Carbon(C) = 4
  7. Nitrogen(N) = 3
  8. Oxygen(O) = 2
  9. Fluorine(F) = 1
  10. Neon(Ne) = 0
  11. Sodium(Na) = 1
  12. Magnesium(Mg) = 2
  13. Aluminium(Al) = 3
  14. Silicon(Si) = 4
  15. Phosphorus(P) = 3, 5
  16. Sulphur(S) = 2
  17. Chlorine(Cl) = 1
  18. Argon(Ar) = 0
  19. Potassium(K) = 1
  20. Calcium(Ca) = 2
The valencies of first 20 elements you remember their atomic numbers and find the valencies of them by using their electronic configuration.

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