Lewis dot structure, octet rule for a central atom

In summary, the octet rule is not satisfied for the central atom Xe, which has 2 extra electrons attached to it. This means that for compounds with multiple atoms, it is important to first ensure that the octet rule is satisfied for the exterior atoms before placing any remaining electrons on the central atom. If the central atom has more than 8 electrons attached to it, it is not possible to fix it with multiple bonds. For compounds with only two atoms, such as the acetate ion, a double bond between the two carbon atoms is possible if there are only two hydrogens in the compound. Finally, there can be more than one central atom in a compound, as seen in the example of CH3-CH3 where
  • #1
dramadeur
19
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As you can see, octet rule isn't satisfied for the central atom Xe, it has 2 more electrons attached to it.
So does it mean, that you should first try to make sure octet rule works for any "side" atoms, and then you just put any remaining electrons to a central atom? (or central atoms?) And if Central atom has more than 8 electrons attached to it, you just leave it like that, right? Because there's no way to fix it with multiple bonds, right?

#2
vM0pudHl.png

I understand why double bond is impossible between two Carbons here, but what if there were only two Hydrogens in the compound (acetate ion), would it mean that there could be a double bond between Carbons as well?

#3. Lastly, can there be more than 1 central atom? Like in the previous example, both C are central atoms, right?
 
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  • #2
For point 1, you pretty much got the picture. Indeed what you call 'exterior' atoms do indeed have the smallest number of covalent bonds, so their octet structure is easier to achieve. Because you can't get a Florine atom to have a double bond (that would ruin its octet, Florine is the only one for which its octet is holy), it is always an 'exterior' atom.

Point 3. It's correct. CH_3-CH_3 is another example.
 
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1. What is a Lewis dot structure?

A Lewis dot structure is a diagram that represents the valence electrons of an atom or molecule. It uses dots to represent the valence electrons and lines to represent chemical bonds between atoms.

2. How do you determine the central atom in a Lewis dot structure?

The central atom in a Lewis dot structure is usually the atom with the lowest electronegativity or the one with the most valence electrons. However, there are exceptions to this rule, and it ultimately depends on the molecule's geometry.

3. What is the octet rule?

The octet rule states that atoms tend to gain, lose, or share electrons to achieve a stable configuration with eight valence electrons, also known as an octet. This configuration is similar to the noble gases, which are highly stable due to their full valence shells.

4. Can the octet rule be broken?

Yes, the octet rule can be broken in certain cases. For example, elements in the third row and beyond on the periodic table can accommodate more than eight valence electrons due to their d-orbitals. Additionally, molecules with an odd number of valence electrons or an incomplete octet can also exist.

5. How do you draw a Lewis dot structure for a molecule with multiple bonds?

To draw a Lewis dot structure for a molecule with multiple bonds, you first need to determine the central atom and its valence electrons. Then, you can draw single bonds between the central atom and the other atoms and distribute the remaining electrons as lone pairs. If there are not enough electrons for each atom to have an octet, multiple bonds may be necessary to complete the octet for each atom.

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