ManzRDH

Dinene RDH, BA
10+ Year Member
15+ Year Member
Sep 9, 2003
50
0
New York
Sulfate (SO4)-2

Can someone exlain the formal charge on oxygen?

I found sulfur's formal charge to be 2 which is correct

Formal Charge= V -1/2 N bonding- N non-bonding
 

vertical bite

Membership Revoked
Removed
10+ Year Member
Feb 19, 2005
214
0
Status
ManzRDH said:
Sulfate (SO4)-2

Can someone exlain the formal charge on oxygen?

I found sulfur's formal charge to be 2 which is correct

Formal Charge= V -1/2 N bonding- N non-bonding


Wow you are having a hard time huh? What exactly are you studying with?

O is always -2

there are 4 Oxygens. 4 x -2 = -8

the sum of the oxidation numbers must = -2

so Sulfur must be 6 !

-8 + 6 = -2

get it?
 

drat

I catch huge fish.
7+ Year Member
15+ Year Member
ManzRDH said:
Sulfate (SO4)-2

Can someone exlain the formal charge on oxygen?

I found sulfur's formal charge to be 2 which is correct

Formal Charge= V -1/2 N bonding- N non-bonding
First, congrats on knowing the difference between formal charge and oxidation number, unlike vertical bite. :thumbup:

It's easiest if you draw the Lewis dot structure for sulfate...I can't do it on the computer here...

But, you're right, the equation to calculate the formal charge is:
# of valence electrons - # of non bonding electrons - (1/2)*# of bonding electrons.

Look at the Lewis dot structure. . .
For the S, you have 6 valence electrons, 0 nonbonding electrons, and 8 bonding electrons....plug these values into the question and you get 2, like you said.

6 - 0 - (1/2)*8 = 2

For O, you have 6 valence electrons, 6 nonbonding electrons, and 2 bonding electrons....plug these values into the question and you get -1

6 - 6 - (1/2)*2 = -1
 

vertical bite

Membership Revoked
Removed
10+ Year Member
Feb 19, 2005
214
0
Status
OH I got burned !!!

Finally someone in these forums with brains.

Ugly dog but brains.......
 

luder98

Senior Member
10+ Year Member
5+ Year Member
Sep 17, 2004
652
0
Status
Dentist
drat said:
First, congrats on knowing the difference between formal charge and oxidation number, unlike vertical bite. :thumbup:
And oxygen's oxidation number is not always -2. :laugh:
 

vertical bite

Membership Revoked
Removed
10+ Year Member
Feb 19, 2005
214
0
Status
Good god who cares ????

Ok I think its gonna be darn rare to see a peroxide question.

MAn.............................
 

drat

I catch huge fish.
7+ Year Member
15+ Year Member
luder98 said:
And oxygen's oxidation number is not always -2. :laugh:
'Tis true. Peroxides are the exception where O is -1. But it wasn't me who said O is always -2!! Don't go mixing me and Vert up. I'm utterly offended. :)

But, let's not talk about oxidation 'cause the OP had a question about formal charge...No need for confusion -- but it's important to recognize there IS a difference!
 

vertical bite

Membership Revoked
Removed
10+ Year Member
Feb 19, 2005
214
0
Status
Peroxides?


I posted that above you.


READ.

I swear its hard being so smart.

I am in dental school. are you ?
 

vertical bite

Membership Revoked
Removed
10+ Year Member
Feb 19, 2005
214
0
Status
drat said:
'Tis true. Peroxides are the exception where O is -1. But it wasn't me who said O is always -2!! Don't go mixing me and Vert up. I'm utterly offended. :)

But, let's not talk about oxidation 'cause the OP had a question about formal charge...No need for confusion -- but it's important to recognize there IS a difference!


Id bet $100 that you have to look that up..........
 

drat

I catch huge fish.
7+ Year Member
15+ Year Member
vertical bite said:
Id bet $100 that you have to look that up..........
:laugh: okay. i win. i'm awesome. go me.

i'm a chemist so if i didn't know the answer to that question, i'd be pretty pathetic. but i'm willing to entertain other chemistry questions if you'd like to try and stump me. :luck:
 

vertical bite

Membership Revoked
Removed
10+ Year Member
Feb 19, 2005
214
0
Status
drat said:
:laugh: okay. i win. i'm awesome. go me.

i'm a chemist so if i didn't know the answer to that question, i'd be pretty pathetic. but i'm willing to entertain other chemistry questions if you'd like to try and stump me. :luck:


Well good stuff then.

I rem. it too but have never seen it EVER come up so sue me.

:scared:
 

luder98

Senior Member
10+ Year Member
5+ Year Member
Sep 17, 2004
652
0
Status
Dentist
drat said:
'Tis true. Peroxides are the exception where O is -1. But it wasn't me who said O is always -2!! Don't go mixing me and Vert up. I'm utterly offended. :)

But, let's not talk about oxidation 'cause the OP had a question about formal charge...No need for confusion -- but it's important to recognize there IS a difference!
Of course I knew that it wasn't you. I only wanted to add to your comment. BTW, it can also be +1 when it's in a compound with a more electronegative element like F. I do not want to outsmart anyone here because I know I'm just an average Joe and there are plenty of people (you are one of those) on this forum who are definitely smarter/better than me. I'm sure you know my intention.
 

drat

I catch huge fish.
7+ Year Member
15+ Year Member
luder98 said:
Of course I knew that it wasn't you. I only wanted to add to your comment. BTW, it can also be +1 when it's in a compound with a more electronegative element like F. I do not want to outsmart anyone here because I know I'm just an average Joe and there are plenty of people (you are one of those) on this forum who are definitely smarter/better than me. I'm sure you know my intention.
Ah yes, I suppose that is the case for OF2 and such. Good stuff, luder98. Hadn't really thought of that!! I love chemistry!

But for future DAT takers, don't worry about such a rare occurance! :)