CBSE Class 11-science Answered

The Lewis structure model generally follows the octet rule and provides a framework to understand covalent bonding. Lewis structures represent valence electrons as dots and bonding electrons as lines. Lewis structures do not represent inner electrons; only valence electrons are shown.

Here is a step-by-step procedure for writing valid Lewis structures for any given molecular formula:

1. Count the total number of valence electrons by summing the group numbers of all the atoms. If there is a net positive charge, subtract that number from the total electron count. If there is a net negative charge, add that number to the total electron count.
2. Draw single bonds to form the desired connectivity.
3. Add lone pairs and multiple bonds, keeping the octet rule in mind.
4. Add formal charges as needed.

Level 1 (basic)

1. Add up all the valance electrons of the atoms involved.  ex CF₄   

     So C has 4 and F has 7 (x4  we have 4Fs) = 32 valence electrons

2. You need to pick the central atom. This is usually easy, this atom will be surrounded by the others. Never H.

 So C will be surrounded by F's.

3. Now we create our skeleton structure by placing bonds in. A bond is a dash that represents 2 electrons.