Lewis Structure Problem, Atoms of more than 8 valence electrons?

Click For Summary

Discussion Overview

The discussion revolves around the complexities of drawing Lewis structures, particularly focusing on atoms with more than eight valence electrons, such as gold. Participants explore the nature of valence electrons, bonding in metallic versus non-metallic compounds, and the electronic configurations relevant to these concepts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants express confusion about how to construct Lewis structures, likening it to balancing equations and questioning how to connect atoms with many valence electrons.
  • It is noted that only valence electrons in the outermost orbital are necessary for Lewis structures, and that metallic compounds typically form ionic bonds rather than covalent ones.
  • Participants discuss the specific electrons to consider for gold, questioning whether to include d electrons or s electrons in the bonding process.
  • A participant provides the electronic configuration of gold, suggesting that both 5d and 6s orbitals are involved in bonding, particularly in the Au3+ state.
  • One participant elaborates on the concept of electron shells and orbitals, explaining the need for atoms to achieve a stable configuration, often described as having eight electrons in the valence shell, while also detailing the quantum numbers associated with electrons.
  • Examples of molecular structures, such as methane (CH4) and water (H2O), are used to illustrate how atoms achieve stable configurations through bonding.
  • There is a detailed explanation of covalent bonding and the significance of double bonds in molecular structures like O2 and O3.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the best approach to drawing Lewis structures for atoms with many valence electrons, and there are multiple competing views regarding the treatment of electrons in bonding, particularly for metallic elements like gold.

Contextual Notes

Participants express uncertainty regarding the inclusion of various electron types in bonding considerations and the implications of quantum mechanics on electron arrangement and bonding stability.

relativitydude
Messages
70
Reaction score
0
I am confused. Doing Lewis structures is like balancing an equation, putting it together till all the valence electrons work with each other, as far as I can tell. :-p

However, some atoms have A TON of valence electrons, like gold which has 25, um, how would I connect it to other elements?

Also, when I see O superscript 3- that just means there are three extra valence electrons?
 
Chemistry news on Phys.org
You don't need to include all of the electrons; only valence electrons (the ones in the outmost orbital) are enough.

Remember that Lewis structures work best with ametalic ones, metallic compounds tend to form ionic bonding.

When you see something like O3-, you can conclude that there are three extra electrons added to the neutral atomic state. They will be valence electrons, as lower energy levels are already occupied.
 
chem_tr said:
You don't need to include all of the electrons; only valence electrons (the ones in the outmost orbital) are enough.
What electrons should be accounted for when looking at gold? Just the d electrons, or the s electrons as well?
 
Let me write the electronic configuration of gold to see how many electrons are available in the valence shell:

[tex]Au_{79}=[Xe]4f^{14}~5d^{10}~6s^1[/tex]

It seems that 5d and 6s orbitals will be used in bonding. In [itex]\displaystyle Au^{3+}[/itex], the configuration will end with [itex]\displaystyle 5d^8[/itex].
 
Thank you for all your help
 
Electrons are attracted to protons, but repell electrons. So, instead of all the electrons being bunched up right next to the nucleas, they orbit around the nucleas in shells. These shells can sometimes contain sub-shells. For example, the first shell contains only one sub-shell. As an electron gets further away from it's atom, it must have more "quantum energy." Electrons want to get as close to the nucleas as possible, but according to quantum physics, no to electrons can have the same "quantum energy." So, they orbit in shells. The electrons orbit in orbitals. The sub-shells have orbitals. For example, the 1 shell has an S orbital. Because it's an s orbital and it's the first shell it's labelled 1S. For 1-First shell-, S-S orbital. An S orbital has the shape of a sphere. An orbital wants to fill it's self. Alright, so why would the atom want to have 8 electrons in it's outer most shell, good question. The second shell has two sub-shells. One sub-shell has an S orbital, and the second has three P orbitals. The reason it has three is because they can arrange themselves according to X,Y,Z. Each orbital has only two electrons, because no two electrons can have the same "quantum energy." So, for the valence shell of an atom with two shells, one S orbital and three P orbitals. Two electrons an orbital adds to...8. Hydogen, on the other hand, only has one shell. So, to fill it's valence shell, it only needs two electrons. It already has one - Hydogen = one proton, one electron - so, it only needs to bond with one atom to fill itself. Carbon, on the other hand, has two shells, so it needs 8 to fill it's valence shell. So...

H
H C H Methane! CH4.
H

If you were to count it up everyone's filled. The carbon atom has 6 electrons. 2 in it's first shell, and 4 in it's valence shell. It needs 8 in it's valence shell. So, it shares one with hydrogen, and the hydrogen shares one of the carbons. This gives the carbon an extra electron, and the hydrogen it's desired two. The carbon, then, bonds with three more to add to 8.

HOH Water! H20. Oxygen has six valence electrons, meaning it needs 2 to gain, which it does with 2 hydrogen molecules.

O=O Oxygen! O2.

You're probably wondering, why is there an equals sign between the Oxygen molecules?
This indicated a double bond. Oxygen has six valence electrons, when it bonds with another oxygen, it gets 7. That's not the desired 8. So, it makes a double bond, and they share two electrons each. Which adds to 8.

O
O O Ozone! O3. Each one of these atoms share with each other, making 8.

That's covelant bonding!
This "quantum energy I told you about is somewhat true. What's really true is that there are four "quantum numbers" that cannot match.
The first is N.
N is the energy of an electron. For example, an electron in the first shell would have an N of 1. An electron in the second shell would have an N of 2. An electron in the third shell would have an N of 3.
N=1, means it's in the first shell.
The second is L. It's actually a greek cursive L kind of like this. l. Okay. This sign is the orbital. L = N - 1. That's the equation. So, if N = 1, then, L = 0. 0 is an S orbital.
If N = 2, L can equal either 0 or 1. If it is 1, that's a P orbital. If N = 3, then that can be either 0,1 or 2. An S,P or...a D orbital.
Now, the third quantum number is M. It is the orientation of the orbitals, you know XYZ.
M can equal anything between -L and +L. For example if L is 1, then M can equal -1,0,1.
This is 3 different ways of arranging the P orbital.
Now the final one is Ms. For Spin. The spin of the electron can equal - 1/2 or 1/2.

Okay, so let's look at the possible arrangements of some electrons.

N L M Ms
1 0 0 -1/2
1 0 0 1/2 First shell, only can have two electrons.

2 0 0 -1/2
2 0 0 1/2
2 1 -1 -1/2
2 1 -1 1/2
2 1 0 -1/2
2 1 0 1/2
2 1 1 -1/2
2 1 1 1/2 Second shell, eight electrons, but none of them, nor the one's in the first shell have the same 4 quantum numbers.

HOPE YOU UNDERSTAND. IT TOOK ME A WHILE TO WRITE, I'D HATE TO LOSE IT AT THE LAST MOMENT, LIKE THE POWER SHUT DOWN OR SOMETHING. IF YOU UNDERSTAND THIS, YOU WILL UNDERSTAND THE REST.
HERE'S SOME SITES.

http://chemed.chem.purdue.edu/gench...h6/quantum.html

http://lectureonline.cl.msu.edu/~mm...od/electron.htm
 
Last edited by a moderator:

Similar threads

  • · Replies 5 ·
Replies
5
Views
6K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 9 ·
Replies
9
Views
15K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 4 ·
Replies
4
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K