chemical bonding shapes and angles

[purker]

So i was given these questions to do by my teacher and for 27, not only was she unable to help with the question but even didnt know about shapes of molecules. Can somebody pls teach how I can identify shapes from just looking at an equation plss. Also, my teacher couldnt even do 17.... shes the one who gave out the homework... i really need help

 

cheers

[CaptainPanic]

Surely you were not just given these questions, without any textbook explanation or other resource? Look into whatever source you have, and try to understand the shapes of molecules. It is not very hard, actually, but being a good student will require that you look into the resources you were given.

 

For example, Q17, those 4 answers (A, B, C and D) come from somewhere. Find where in your books/handout these numbers are explained, and you will probably find the answer to all your problems.

[hypervalent_iodine]

You should be familiar with VSEPR if you are doing these sorts of questions. Have a look at the central atom in each case, count the number of electron sets around it (i.e. the sum of the number of things bonded to it and lone pairs) and have a think about what sort of geometry it would adopt for all of those sets to be as far away from each other as possible. Remember also that we ignore the space occupied by lone pairs when we describe the shape of a molecule. If you have a copy of Blackman, there is a good reference list that allows you determine geometry based on this.