CHEM 1A03 Chapter Unit 5 Module 2: Unit 5- Module 2 – Chemical Bonding II

• School: McMaster University
• Department: Chemistry
• Course: CHEM 1A03
• Professor: Lydia Chen

Document Summary

Unit 5: module 2 chemical bonding ii. When more than one lewis structure can be drawn, the molecule or ion is said to have resonance. In order to minimize charges in the structure, one double bond is formed by sharing a pair of electrons from o to p. The electrons from oxygen used to form this bond could have been used from the top, right, left or bottom side of the oxygen atom so there are 4 equivalent charge-minimized structures known as resonance structures. Since the electrons are always moving, the true structure of phosphate is(cid:374)"t a(cid:374)(cid:455) of the 4 stru(cid:272)tures i(cid:374)di(cid:448)iduall(cid:455), (cid:271)ut rather an average of them this is called a resonance hybrid. Because it is an average, the charges are actually divided over all the oxygen atoms and the average formal charge is calculated. The double bond is also distributed between all of the oxygen atoms, and we get an average bond order as well.