i had the same doubt as groundedpisces.....i do understant ur xlanation....but is the mechanism of the reactions involved in the formation of compounds the only way to find the no. of lone pairs on the atom?
@anuvrathanarasimhan Hi anuvrathanarasimhan, thanks for the question. I was using the acid-base example with groundedpisces above just to help visualize where those electrons were coming from. but no, a mechanism isn't required to figure out lone pairs on an atom.For example, you can just be given the cpd H2O and asked to draw its lewis structure. Each H comes with 1 e-, O comes with 6 e-'s. That means you have to figure out how to put 2 H's and an O together using those 8 total e-'s.(cont-->)
The only feasible way to do that is to have the H's single bonded to the O and 2 lone pairs on the O. so in that sense, you did not need to have a mechanism for a reaction to determine the number of lone pairs. it's just knowing how to draw a lewis structure. Hope that helps! groundedpisces, if you're still around and can offer another explanation for how this eventually made sense for you, that'd be great! Happy studying!
I feel like I missed something.. I accept that Oxygen wants 6 val. e- around it, but it also wants to be neutral. However, I dont understand why Oxygen in H3O only has a lone pair up top, shouldn't it have 3 lone electrons left over?
@ 1:58: It shares 1 atom with 3 different hydrogens, vice versa. Since it started with 6 atoms around it, shouldn't the O be left with 3 lone electrons - can you help me understand?
Remember that Oxygen wants 6 valence e-'s DIRECTLY around it to be neutral, but it still wants a total of 8 valence e-'s to fill its octet to be stable (this was discussed in OChem Basics I - pt 2).
I think I understand your confusion, but correct me if I'm wrong. Are you imagining that the O starts out with 6 e-'s, and the 3 H's start out with 1 e- each, & so when they get together there would be a total of 9 e-'s around O?
That's not actually what's going on. Let's clarify the situation with an acid-base example. (This will definitely be clearer when you watch the "Acids & Bases" video)
If we look at H - O - H (aka H2O). The Oxygen of H2O has 2 lone pairs around it in addition to being bonded to 2 H's right?
H2O becomes H3O+ by using one of Oxygen's lone pairs to pick up (de-protonate) a H from an acid. Say for example H2O reacts with H-Cl. H2O is the base. H-Cl is the acid. The O of H2O will use one of its lone pairs to pull off (bond to) the H from H-Cl. When O pulls off this H, the H doesn't come with any e-'s. The e-'s that were being shared between H & Cl will all go to Cl...thus it will become Cl(-)...
i had the same doubt as groundedpisces.....i do understant ur xlanation....but is the mechanism of the reactions involved in the formation of compounds the only way to find the no. of lone pairs on the atom?
anuvrathanarasimhan 3 weeks ago
@anuvrathanarasimhan Hi anuvrathanarasimhan, thanks for the question. I was using the acid-base example with groundedpisces above just to help visualize where those electrons were coming from. but no, a mechanism isn't required to figure out lone pairs on an atom.For example, you can just be given the cpd H2O and asked to draw its lewis structure. Each H comes with 1 e-, O comes with 6 e-'s. That means you have to figure out how to put 2 H's and an O together using those 8 total e-'s.(cont-->)
CrackOChem 3 weeks ago
@anuvrathanarasimhan (--> cont)
The only feasible way to do that is to have the H's single bonded to the O and 2 lone pairs on the O. so in that sense, you did not need to have a mechanism for a reaction to determine the number of lone pairs. it's just knowing how to draw a lewis structure. Hope that helps! groundedpisces, if you're still around and can offer another explanation for how this eventually made sense for you, that'd be great! Happy studying!
CrackOChem 3 weeks ago
Comment removed
Rochabp 4 months ago
thanks so much for these videos. i was so lost in orgochem i prayed for help and there u were. good fundamentals thnx ah million : )
dtrue07 4 months ago
I feel like I missed something.. I accept that Oxygen wants 6 val. e- around it, but it also wants to be neutral. However, I dont understand why Oxygen in H3O only has a lone pair up top, shouldn't it have 3 lone electrons left over?
@ 1:58: It shares 1 atom with 3 different hydrogens, vice versa. Since it started with 6 atoms around it, shouldn't the O be left with 3 lone electrons - can you help me understand?
GroundedPisces 4 months ago in playlist CrackOChem_OChem Basics I
@GroundedPisces Hello & thanks for the question.
Remember that Oxygen wants 6 valence e-'s DIRECTLY around it to be neutral, but it still wants a total of 8 valence e-'s to fill its octet to be stable (this was discussed in OChem Basics I - pt 2).
I think I understand your confusion, but correct me if I'm wrong. Are you imagining that the O starts out with 6 e-'s, and the 3 H's start out with 1 e- each, & so when they get together there would be a total of 9 e-'s around O?
(cont -->)
CrackOChem 4 months ago
@GroundedPisces (--> cont)
That's not actually what's going on. Let's clarify the situation with an acid-base example. (This will definitely be clearer when you watch the "Acids & Bases" video)
If we look at H - O - H (aka H2O). The Oxygen of H2O has 2 lone pairs around it in addition to being bonded to 2 H's right?
(cont 2 -->)
CrackOChem 4 months ago
@GroundedPisces
(--> cont 2)
H2O becomes H3O+ by using one of Oxygen's lone pairs to pick up (de-protonate) a H from an acid. Say for example H2O reacts with H-Cl. H2O is the base. H-Cl is the acid. The O of H2O will use one of its lone pairs to pull off (bond to) the H from H-Cl. When O pulls off this H, the H doesn't come with any e-'s. The e-'s that were being shared between H & Cl will all go to Cl...thus it will become Cl(-)...
(cont 3 -->)
CrackOChem 4 months ago
@GroundedPisces
(--> cont 3)
and now O instead of having 2 lone pairs, only has one lone pair, and the other was used to bond to the H.
Sorry I had to split that up into several separate comments because of the youtube character limit, but does that make sense?
CrackOChem 4 months ago