[newbie!]

in chemistry. TESTED.
(well not ever) but my degree involves taking these exams that are called "generals" at the end of our degree (ie. in our 4th year).
it tests us on everything we have learnt from 1st year through to 4th year as an under graduate.
i'm currently in 3rd year and revising some of this stuff though most of it i;ve forgotten :/
help would be apprecieated on the following questions. they come from varous diferent courses i have studied so far tbh i cant even remember the names of the courses hence the pretty vague name of this thread.
 i've tried to include my thought process and attempt at working as far as possible.


1) Consider an ion (charge –1) containing one C, one N and one O atom.   Work out its most likely Lewis structure (briefly give reasons for your choice) and any possible resonance contributors. Use the VSEPR model to work out its shape. 


shall be adding more q's in time

[newbie!]

more questions:

3) The question concerns the various types of isomers of the formula C6H11BrO
A.   Draw two alkenes with this formula which are E and Z isomers.
B.   Give the systematic names for your answer in part A.
C.   Draw two cyclic enantiomeric compounds with this molecular formula, one of which is R-configuration and one of which is S-configuration.


4) This question is about the SN2 reaction.
(a)   Explain three features of the SN2 reaction.   
(b)   For the following reaction, draw a mechanism and the product(s).
 
(c)   Draw and explain the reaction profile for this reaction. 

here are my answers:

[sjb]

more questions:

3) The question concerns the various types of isomers of the formula C6H11BrO
A.   Draw two alkenes with this formula which are E and Z isomers.
B.   Give the systematic names for your answer in part A.
C.   Draw two cyclic enantiomeric compounds with this molecular formula, one of which is R-configuration and one of which is S-configuration.


4) This question is about the SN2 reaction.
(a)   Explain three features of the SN2 reaction.   
(b)   For the following reaction, draw a mechanism and the product(s).
 
(c)   Draw and explain the reaction profile for this reaction. 

here are my answers:

3) The alkene isomers you have drawn are not correctly labelled E and Z - check your naming conventions here. Although the hypobromite structures you have drawn possibly exist, are there simpler structures you can draw? Remember a double bond equivalent is not just a double bond, you can have a ring instead for the second part?

4) Looks reasonable, though you have not really explained the transition state(s) of the reaction, I think that is what the second part is trying to get at.