CHEM1011 Lecture Notes - Lecture 14: Sigma Bond, Bond Length, Benzene
9 Jun 2018
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Lecture 14: Lewis structures resonance
LECTURE 13 CONTINUED
Bond lengths and energies
The length of a bond and energy it takes to break a bond depends on the type of bond
- Single bonds are longer and weaker than double bonds
- Double bonds are longer and weaker than triple bonds
Electrons in single bonds
- The pair of electrons orbit directly between the two atoms
- This is called a σ siga od
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find more resources at oneclass.com
2
Electrons in double and triple bonds
In double bonds:
- The first bond is a sigma bond
- The second pair of electrons orbit above and below the sigma bond
- This bond is called π bonds
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In triple bonds:
- The first bond is a sigma bond
- The second and third bonds are π bonds
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The length of a bond and energy it takes to break a bond depends on the type of bond. Single bonds are longer and weaker than double bonds. Double bonds are longer and weaker than triple bonds. The pair of electrons orbit directly between the two atoms. This is called a (cid:894)sig(cid:373)a(cid:895) (cid:271)o(cid:374)d. The second pair of electrons orbit above and below the sigma bond. The first bond is a sigma bond. The second and third bonds are bonds. Too hard to get them to bend into triangle. May occasionally see a square because it is less strained. When two or more lewis structures are possible for a molecule, it is said to exhibit resonance. This is indicated by a double headed arrow. This does not mean the molecule flips back and forth between the possible structures- the true structure is actually an average of the possible resonance structures.
