## 2B. 1C

JamieVu_2C
Posts: 108
Joined: Thu Jul 25, 2019 12:16 am

### 2B. 1C

The problem asks you to draw the Lewis structure for ONF. So, the structure has N as the central atom, with a double bond between O and N and a single bond between N and F. But why can't you put the double bond between N and F and the single bond between O and N?

Jasmine Vallarta 2L
Posts: 102
Joined: Sat Aug 17, 2019 12:18 am

### Re: 2B. 1C

F has 7 valence e-, so it can only make 1 single bond. O has 6 valence e-, so it can make a double bond or 2 separate single bonds

MAC 4G
Posts: 121
Joined: Wed Sep 18, 2019 12:16 am

### Re: 2B. 1C

Going off the explanation above, when you are drawing Lewis structures it's best to think about the octet rule, in which every element has 8 e- in the outer most shell (through sharing valence e- in this case). But, there are a few exceptions (the slides mention the exceptions as H, He, Li, and Be) and we later learned that in the section about resonance P, S, and Cl are exceptions to the octet rule.

Manav Govil 1B
Posts: 104
Joined: Sat Sep 07, 2019 12:19 am

### Re: 2B. 1C

You can also try checking the formal charge. If we were to put a double bond between the N and the F, and a single bond between the N and the O, the formal charge for F would be +1, and the formal charge for O would be -1. This is worse than the zero formal charges across the board when the double bond is between the O and the N, and the single bond is between the N and the F. Therefore, the latter is more stable and accepted.

Annie Chantasirivisal_4G
Posts: 114
Joined: Wed Sep 18, 2019 12:21 am

### Re: 2B. 1C

Continuing from this, how would we know which atom would be the central atom? The book stated that "usually" the central atom would be listed first, but for ONF this clearly was not the case... how could we tell from the "usually" and exceptions?

CynthiaLy4F
Posts: 103
Joined: Sat Jul 20, 2019 12:16 am

### Re: 2B. 1C

It's better to put a double bond between O and N and a single bond between N and F because this structure has all the formula charges as 0, which means it is the most stable.