C, N, O, and F

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Riya Sood 4G
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Joined: Sat Aug 24, 2019 12:18 am

C, N, O, and F

Postby Riya Sood 4G » Mon Nov 04, 2019 10:29 am

Do C, N, O, and F always follow the octet guideline even if their formal charge is not 0?

Brian_Ho_2B
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Re: C, N, O, and F

Postby Brian_Ho_2B » Mon Nov 04, 2019 11:53 am

Riya Sood 4C wrote:Do C, N, O, and F always follow the octet guideline even if their formal charge is not 0?

Because they're located in period 2, where n=2, those atoms do not have access to an empty d-block where they can form bonds transcending the octet rule; therefore, they will pretty much always follow the octet rule in covalent bonding. Formal charge and octet rule aren't dependent on each other; the way you form an octet for C, N, O, or F will determine whether the formal charge is zero or not.

EmilyJoo_1G
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Re: C, N, O, and F

Postby EmilyJoo_1G » Wed Nov 06, 2019 12:24 pm

Yes. They must follow the octet rule where as elements in energy level three and higher can hold more than eight electrons since they have an empty d-orbital.

805394719
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Joined: Wed Sep 11, 2019 12:16 am

Re: C, N, O, and F

Postby 805394719 » Wed Nov 06, 2019 12:28 pm

Yes, they have to follow the octet rule because they cannot have an expanded octet since they are in the second period and do not have the shell n=3. Therefore, they do not possess a d orbital which can hold up to 10 electrons and therefore allow the atom to expand its octet. Atoms in the first and second period only have up to 2p which can hold up to 6 electrons and thus they can only have a max of 8 electrons in their valence shell which is n=2 since the second shell only has the orbitals s and p.

Robert Tran 1B
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Re: C, N, O, and F

Postby Robert Tran 1B » Wed Nov 06, 2019 12:51 pm

There are some exceptions to the octet rule for these atoms. For example, CH3 is a radical, so it only has seven electrons around it, which breaks the octet rule.

Audrie Chan-3B
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Re: C, N, O, and F

Postby Audrie Chan-3B » Thu Nov 07, 2019 11:08 am

The elements that can have expanded octet are P, S, and Cl.

EvaLi_3J
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Re: C, N, O, and F

Postby EvaLi_3J » Thu Nov 07, 2019 12:57 pm

Yes, I believe they have to follow the octet rule as they can only have valence electrons as many as eight. Formal charges definitely don't have to be 0, even though the formal charges that are close to 0 makes the molecule more stable.

Kaitlyn Jang 1F
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Joined: Sat Aug 17, 2019 12:16 am

Re: C, N, O, and F

Postby Kaitlyn Jang 1F » Sat Nov 09, 2019 10:26 am

C, N, O, and F must follow the octet rule at all times. Atoms can begin having expanded octets at period 3 or greater. Typical atoms with expanded octets include sulfur, phosphorus, and silicon (all of which are in period 3).

KHowe_1D
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Re: C, N, O, and F

Postby KHowe_1D » Sat Nov 09, 2019 10:49 am

Yes they will follow the octet rule even if that makes the formal change not equal to 0 because having 8 electrons in the outer shell is where an atom is most stable.

Emil Velasco 1H
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Re: C, N, O, and F

Postby Emil Velasco 1H » Sat Nov 09, 2019 10:09 pm

These four elements C, N, O, F follow the Octet guideline as they do not have access to the expanded octets found with the d block

Celine 1F
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Re: C, N, O, and F

Postby Celine 1F » Sun Nov 10, 2019 12:18 am

Because they are located in period two, where there is no d block for the electrons to backfill.

Lauren Stack 1C
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Re: C, N, O, and F

Postby Lauren Stack 1C » Sun Nov 10, 2019 2:51 pm

As Carbon, Nitrogen, Oxygen, and Fluorine are all located in period 2 of the periodic table, their valence electrons are found in n=2. Thus, they do not have the extra 3d subshell that would allow them to have an expanded octet an must follow the octet guideline. Furthermore, although we try to minimize it in Lewis Structures, you do not always have to have a formal charge of 0.

Ryan Juncker 3D
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Joined: Wed Sep 18, 2019 12:18 am

Re: C, N, O, and F

Postby Ryan Juncker 3D » Sun Nov 10, 2019 2:58 pm

Yes, even if the formal charge or C,N,O or F is not zero they will follow the octet rule because they are period 2 elements and do not have a d shell to fill up with electrons.

Claire Stoecklein 1E
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Joined: Sat Jul 20, 2019 12:15 am

Re: C, N, O, and F

Postby Claire Stoecklein 1E » Sun Nov 10, 2019 10:15 pm

A good guideline to follow for drawing organic structures is that carbon wants 4 bonds, nitrogen 3, oxygen 2, and hydrogen 1.


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