## Drawing Lewis Structures

Ally Huang- 1F
Posts: 103
Joined: Thu Jul 25, 2019 12:16 am

### Drawing Lewis Structures

What is the best way to know how to draw lewis structures and where to put double bonds or single bonds? For example, how do you know where to put double bonds in ClO4-?

Abigail_Hagen2G
Posts: 107
Joined: Fri Aug 09, 2019 12:17 am

### Re: Drawing Lewis Structures

If there are multiple places you can place the double bond, that shows resonance. But you'll want to limit the formal charges on each atom.

Emily_4B
Posts: 57
Joined: Wed Sep 18, 2019 12:21 am

### Re: Drawing Lewis Structures

I believe this is where finding the formal charges for each atom comes in and then placing the double bonds in a position that creates the lowest formal charge possible

Abby Soriano 1J
Posts: 103
Joined: Sat Aug 24, 2019 12:16 am

### Re: Drawing Lewis Structures

Whenever you draw Lewis structures, you want to follow 3 steps:
1) Ensure that you have the correct number of valence electrons
2) Try to satisfy the octet rule when you can (be mindful of exceptions)
3) Try to get the lowest formal charges possible on each element

You start off everything with single bonds, and just begin to add double bonds when you're trying to fulfill the octet rule in a way that gives you the smallest formal charges.

Posts: 125
Joined: Sat Aug 17, 2019 12:17 am

### Re: Drawing Lewis Structures

Ally Huang- 1E wrote:What is the best way to know how to draw lewis structures and where to put double bonds or single bonds? For example, how do you know where to put double bonds in ClO4-?

With drawing Lewis Structures, the most important things is to draw the proper amount of electrons and the placement of the atoms (most electropositive in center). Knowing where the double and single bonds are located is based on the formal charges. First, calculate the formal charge or each atom. Then if the formal charge is negative, try to add a double bond to that atom and add lone pairs to make up the 2 e-. Do the opposite for a positive formal charge. Remember that you can have an expanded octet if n = 3 or if the element is after P.