Q4 of 18 Page 226

Why do only valence electrons involve in bond formation? Why not electron of inner shells? Explain.

Electrons in the inner shells are strongly attracted by the nucleus and are stable thereby they don’t involve in bond formation. The electrons in the outermost shells of atoms are called valence electrons which are highly active an are weakly attracted by the nucleus of atom. So they are easily transferred or migrated, so undergo chemical reactions.


More from this chapter

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2

Explain the difference between the valence electrons and the covalence of an element.

 3

A chemical compound has the following Lewis notation:

a) How many valence electrons does element Y have?


b) What is the valency of element Y ?


c) What is the valency of element X ?


d) How many covalent bonds are there in the molecule?


e) Suggest a name for elements X and Y.


 5

Explain the formation of sodium chloride and calcium oxide on the basis of the concept of electron transfer from one atom to another atom.

 6

A. B. and C are three elements with atomic number 6, 11 and 17 respectively.

i. Which of these cannot firm ionic bond? Why?


ii. Which of these cannot form covalent bond? Why?


iii. Which of these can form ionic as well as covalent bonds?