Lewis Structure Stability

Moderators: Chem_Mod, Chem_Admin

904564128
Posts: 21
Joined: Fri Sep 25, 2015 3:00 am

Lewis Structure Stability

Postby 904564128 » Wed Oct 14, 2015 5:23 pm

Since many Lewis structures have a more stable and less stable option, does that mean for every Lewis structure we draw, we should always be checking if there is a more stable option? Is there any sort of way to quickly decide if a molecule will have multiple options by just looking at the formula?

Chem_Mod
Posts: 18709
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 631 times

Re: Lewis Structure Stability

Postby Chem_Mod » Wed Oct 14, 2015 10:01 pm

Yes, when you are drawing lewis structures, you should be evaluating your structure to determine if it is the most stable version. Following the rules for drawing lewis structures should help guide you in determining this. Calculating the formal charge is also a good tool. To my knowledge, there is not a way to know how many reasonable resonance structures exist for a molecule just by looking at its formula, but as you practice drawing structures and become more fluent in molecular structure, you will begin to see patterns and understand what structures certain atoms or molecules are likely to have.

Kelly McBratney 1C
Posts: 23
Joined: Fri Sep 25, 2015 3:00 am

Re: Lewis Structure Stability

Postby Kelly McBratney 1C » Thu Oct 15, 2015 11:45 pm

Does the order in which the elements are listed in the molecule name give any clue as to how the Lewis structure should be drawn? For example, in an element such as CH2COCH3-, can we gain a general idea of how the structure should look solely based on the order of the elements given?

Chem_Mod
Posts: 18709
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 631 times

Re: Lewis Structure Stability

Postby Chem_Mod » Fri Oct 16, 2015 12:33 am

Yes, sometimes the order in which they are written often corresponds to how the atoms are connected. In your example, (i'm going to modify it to CH3COCH3 aka "acetone"), the first carbon is connected to 3 hydrogens and another carbon, the second carbon is bonded to the first and third carbons and 1 oxygen, and the third carbon is bound to the second carbon and 2 hydrogen atoms. However, this molecule could also be written C3H6O, in which there are several different ways in which the atoms can be attached (meaning the different molecules created are isomers!)

Note: this image is missing 2 lone pairs on the oxygen!
Attachments
Acetone.jpg


Return to “Lewis Structures”

Who is online

Users browsing this forum: No registered users and 1 guest