Snape's knowledge of valence shells

post by Bound_up · 2015-04-13T17:58:49.274Z · score: 0 (5 votes) · LW · GW · Legacy · 13 comments

Just a quick question.

Harry James Potter Evans-Verres and the Methods of Rationality: Chapter 18

HJPEV: So, Professor, can you tell me how many electrons are in the outermost orbital of a carbon atom?"

 

Severus's smile widened. "Four," he said. "It is a useless fact which no one should bother writing down, however."

 

Did Snape really know that, or did he read Harry's mind?

 

As to the possibility, this passage,  "Harry stared into Severus's cold gaze and remembered that the Sorting Hat had warned him not to meet anyone's eyes while thinking about - Harry dropped his gaze to Severus's desk." occurs after that already quoted.

 

(If I do something wrong here, which merits a downvote, would you mind specifying the error in question?)


13 comments

Comments sorted by top scores.

comment by TrE · 2015-04-13T18:24:35.972Z · score: 12 (12 votes) · LW · GW

You might want to post this on the hpmor subredit page instead - or in the latest open thread. I don't, however, think that a top-level discussion post is necessary for this.

In any case, Snape saying that the number of valence electrons of carbon is a meaningless fact is weak evidence that he didn't read it in Harry's mind.

comment by Bound_up · 2015-04-13T18:33:41.087Z · score: 1 (1 votes) · LW · GW

Thank you. So, I posted this as a top-level discussion post? What I did is more the kind of thing I should reserve for more substantial posts?

I understand the hpmor subredit, but what do you mean by the latest open thread? Just comment on a recent post in LessWrong discussion? Or forego so doing in favor of finding one specifically about HPMOR?

Thanks again

comment by Algon · 2015-04-13T18:58:10.843Z · score: 1 (1 votes) · LW · GW

Open threads are ones wherein they say something like 'ask any question'.

comment by Bound_up · 2015-04-13T19:15:30.546Z · score: 0 (0 votes) · LW · GW

Gotcha.

So I should have checked for one of those (are they very common?) or created my own.

comment by Algon · 2015-04-13T19:21:05.490Z · score: 0 (0 votes) · LW · GW

I just checked, there's one open for this week.

comment by Algon · 2015-04-13T19:19:04.165Z · score: 0 (0 votes) · LW · GW

I believe there is an 'ask stupid questions' thread for each month, and some other open threads. I'm not sure if you can make open threads yourself, but they're fairly common.

comment by Normal_Anomaly · 2015-04-13T20:34:02.892Z · score: 0 (0 votes) · LW · GW

I think there's an open thread once or twice a month. Also, IMO this post would go better in an open thread than a stupid questions thread; the stupid questions thread is for sharing advice.

comment by Gunnar_Zarncke · 2015-04-13T20:47:09.672Z · score: 0 (0 votes) · LW · GW

Actually the convention is to have a weekly Open Thread. It is usually created by the first person wanting to post an open question when the old thread has expired. That can be you, but please make it run exactly 7 days otherwise you will called to order.

comment by [deleted] · 2015-04-18T21:16:32.754Z · score: 0 (0 votes) · LW · GW

Seems like it would be weak evidence in the other direction... if he thinks it's a useless fact, why does he have it memorized?

comment by Jan_Rzymkowski · 2015-04-13T19:22:05.030Z · score: 9 (13 votes) · LW · GW

Overscrupulous chemistry major here. Both Harry and Snape are wrong. By the Pauli exclusion principle an orbital can only host two electrons. But at the same time, there is no outermost orbital - valence shells are only oversimplified description of atom. Actually, so oversimplified that no one should bother writing it down. Speaking of HOMOs of carbon atom (highest [in energy] occupied molecular orbitals), each has only one electron.

comment by Luke_A_Somers · 2015-04-14T15:32:34.160Z · score: 10 (10 votes) · LW · GW

The notion that (neutral) Carbon has 4 electrons to share and prefers to have 4 electrons shared with it is so oversimplified that no one should bother writing it down?

That is, umm, a surprising viewpoint to me.

comment by falenas108 · 2015-04-14T15:44:07.064Z · score: 4 (4 votes) · LW · GW

It's at least plausible that Snape, as a potions expert who grew up with muggles, thought there might be some connection between potions and chemistry and learned the basics of chemistry.

comment by gattsuru · 2015-04-14T01:55:55.733Z · score: 0 (0 votes) · LW · GW

It's possible that he read it from Harry's mind. Snape is a powerful legilimens, does not believe that anything is cheating when he has to win, Harry had no protection or even deep knowledge of the technique, had to have been thinking of the answer, and hadn't thought to avert his gaze until later.

That said, Severus is more in tune with the Muggle world than most others in the setting, and in Chapter 61 we see Dumbledore treat him as an expert source on muggle technology :

"Severus?" the old wizard said. "What was it actually?" "A rocket," said the half-blood Potions Master, who had grown up in the Muggle town of Spinner's End. "One of the most impressive Muggle technologies."

Later in Chapter 18, we also see the phrase "Common sense is often mistaken for legilimency." Especially as a potions master and someone who retained an interest in muggle chemistry into adulthood, Snape does have more reason than most wizards to know this information. Harry also tends to overestimate both his knowledge, and both he and Quirrel tend to assume the victories of others come from innate differences rather than simple changes in planning or knowledge.

On the other hand, had Snape known that information, it would also mean he could have ended the world accidentally. Dunno what to make of that.