Chapter 4: Structure of Atom- Exercise- 52 A

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Chapter 4: Structure of Atom

Class: IX

Exercise number 52 A

Question 1

How will you find the valency of chlorine, sulphur and magnesium?

Answer 1

If the number of electrons in the outermost shell of the atom is less than or equal to 4, then the valency of the element is equal to the number of electrons in the outermost shell. And if the number of electrons in the outermost shell is greater than 4, then we can determine the valency of that element by subtracting the number of outermost shell  electrons from 8.

The distribution of electrons in chlorine, sulphur, and magnesium atoms are 2, 8, 7; 2, 8, 6 and 2, 8, 2 respectively. Therefore, the number of electrons in the valence shell of chlorine, sulphur, and magnesium atoms is 7, 6, and 2 respectively.

Thus, 

The valency of chlorine = 8 −7 = 1

The valency of sulphur = 8 − 6 = 2

The valency of magnesium = 2