# Guidelines: Writing Organic reaction mechanisms. (Read carefully points & If u know some more points then plz write in comment) 1. A mech. must explain the formation of product(s). 2. A curved arrow is used to indicate the movement of electrons. This convention is often used carelessly, but the arrow does have a precise meaning. The tail shows where the ele. is initially, & the head points to where it will be when the step is complete. WARNING: Many students tend to represent the movement of electrons by arrows that start nowhere & end nowhere. Many students start arrows where there are no electrons. The arrow must start at a point where there are electrons & go to a location to which the electrons will move. 3. Carbonium ions are ions which contain a positively charged carbon atom. The order of carbonium ion stability is: Ter. > Sec. > Pri. 4. Carbanions are ions which contain a negatively charged carbon atom. The order of carbanion stability is: Pri. > Sec. > Ter. 5. Free radicals are electrically neutral. They have no charge. The order of free radical stability is: Ter. > Sec. > Pri. 6. Electrophiles are electron-poor. They attack negative centers in molecules. 7. Nucleophiles are electron-rich. They attack positive centres in molecules. 8. Carbonyl carbon atom, C=O, are electropositive; carbonyl oxygen atoms are electronegative. 9. Never move atoms when changing from one resonance structure to another. Only move electrons! 10. Never mix ionic & free radical mechanisms. If you wish to explain a particular reaction by ionic mechanisms, donot bring in free radicals in any step.
Posted on: Thu, 31 Oct 2013 03:54:48 +0000
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