EN of these atoms: F, O, N, Cl, Br... you get the point

[yestomeds]

Hey, sorry for super simple question.
I read in a prep book that the EN decreases in this order: F O N Cl Br I S C H
Makes sense.

I then watched an online video where it was explained that it starts with F O N C
In other words, Carbon was said to be more electronegative than Cl and S (because the jump from the 3rd up to the 2nd period in EN is dramatic, in other word,s even though atoms like Cl and S are very close to the F, the fact that C is i the 2nd period, also relatively 'close' to the F, makes C greater in EN than are nearby atoms in the 3rd period down).

Hm, might there be a consensus on which is which? I mean I don't even know how important this is or if something like this would show up? Just starting test prep. But it seems like a simple concept so I wasn't sure if at least I should get a very simple concept down? Haha thanks.

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[Cawolf]

Cl is definitely more electronegative than C.

That is the reason that chloroalkanes make good SN2 substrates; the C-Cl bond is polarized towards the Cl.

In general all of the halogens are more electronegative than Carbon, except for Astatine, but that isn't discussed in organic chemistry.

Your acronym of FONClBrISCH is correct.

 

[yestomeds]

Thanks. We've all heard of the acronym FONClBrISCH. But I was watching an MCAT-prep video and the guy emphasized that C, being in period 2, was more EN than was something like Cl or S, which are also "very close" to F.... I mean he emphasized this.

Ahhhhhhhhh..... so just forget that which he emphasized, and go with the acronym?

 

[Cawolf]

Any periodic table with EN values will illustrate the trend for you.

He sounds incorrect.