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Periodic Classification of Elements — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10SciencePeriodic Classification of Elements2 Marks
Question
  1. How do you calculate the possible valency of an element from the electronic configuration of its atoms?
  2. Calculate the valency of an element X whose atomic number is 9.
✓

Answer

  1. The valency of an element is determined by the number of electrons present in the last shell.
If a number of valence electrons are less than or equal to 4 then, valency = a number of valence electrons.

If, the number of valence electrons greater than 4 then, valency = 8 - number of valence electrons.
  1. The electronic configuration of element X with atomic number 9 is 2, 7
Valency of X = 8 - 7 =1

Hence, the valency of the element with atomic number 9 is 1.

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