Nucleophilicity of Benzene and Pyridine

Benzene and substituted benzenes reaet with electrophiles, leading to new functionality. The two-step mechanism involves initial attack by an electrophile to form an intermediate (benzenium ion), followed by elimination of a proton to generate the substituted benzene. 

Display the electrostatic potential map for benzene. Which areas are most electron rich Which are most electron poor Would you expect an electrophile to attack from above and below the plane of the molecule or in the plane of the molecule  

Draw and compare Lewis structures for benzene and pyridine. How many 7C electrons does each molecule have Where are the most accessible electrons in each Display the electrostatic potential map for pyridine and compare it to the corresponding map for benzene. Would you expect electrophilic attack on pyridine to occur analogously to that in benzene If so, should pyridine be more or less susceptible to aromatic substitution than benzene If not, where would you expect electrophilic attack to occur Explain. 

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