Lewis structure Class 11 Notes | EduRev

Chemistry Class 11

Class 11 : Lewis structure Class 11 Notes | EduRev

The document Lewis structure Class 11 Notes | EduRev is a part of the Class 11 Course Chemistry Class 11.
All you need of Class 11 at this link: Class 11

The Lewis Theory

The octet rule:- The Lewis theory gave the first explanation of a covalent bond in terms of electrons that was generally accepted. If two electrons are shared between two atoms, this constitutes a bond and bind the atoms together. For many light atoms, a stable arrangement is attained when the atom is surrounded by eight electrons.

This octet can be made up from some electrons which are totally owned and some electrons which are ‘shared’. Thus atoms continue to form bonds until they have made up an octet of electrons. This is called the ‘octet rule’. The octet rule explains the observed valencies in a large number of cases. There are exceptions to the octet rule; for example, hydrogen is stable with only two electrons. Other exceptions are discussed later.Today, the conventional Lewis structure representation of a pair of bonded electrons is by means of a ‘dash’ (-) usually called a ‘bond’. Lone pairs or ‘non-bonded’ electrons are represented by ‘dots’. Some structures are represented below:


Lewis structure Class 11 Notes | EduRev
Lewis structure Class 11 Notes | EduRev


It is therefore useful to remember some important categories of exceptions:

  • Odd-electron species like NO, NO2, O2 etc. Since it is impossible to distribute an odd number of electrons into pairs, these species necessarily violate the octet rule.
  • The Valence Bond theory handles such species rather clumsily (odd-electron bonds etc.) the molecular orbital theory copes much better.
  • Species in which the central atom `expands' its octet (so to speak) PCl5, SF6, many transition metal compounds etc.
  • Electron -deficient species like BCl3, BeCl2, AlCl3, B2Hetc. in which the central atom has fewer than eight electrons.
Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Related Searches

MCQs

,

video lectures

,

Free

,

ppt

,

Important questions

,

Summary

,

Viva Questions

,

Lewis structure Class 11 Notes | EduRev

,

Previous Year Questions with Solutions

,

Lewis structure Class 11 Notes | EduRev

,

shortcuts and tricks

,

study material

,

Semester Notes

,

Exam

,

Lewis structure Class 11 Notes | EduRev

,

practice quizzes

,

Sample Paper

,

pdf

,

past year papers

,

Objective type Questions

,

Extra Questions

,

mock tests for examination

;