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

In summary: So an electron in the second shell has an L of 1. If N = 3, L can equal 2, or 3. So an electron in the third shell has an L of 3. The third is M. M is the spin of the electron. So, if you have a situation where you have an electron with an N of 1 and an L of 1, it means the electron has a negative spin. If you have an electron with an N of 2 and an L of 1, it means the electron has a positive spin. Remember, these three things are always at odds with each other. So, when you have a compound, it will have a number that's a combination of all three
  • #1
relativitydude
70
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. :tongue2:

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?
 
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  • #2
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.
 
  • #3
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?
 
  • #4
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].
 
  • #5
Thank you for all your help
 
  • #6
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 equasion. 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
 
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1. What are Lewis structures?

Lewis structures are diagrams that show the bonding between atoms in a molecule and the lone pairs of electrons that may exist in the molecule. They are used to predict the shape and properties of a molecule.

2. Can atoms have more than 8 valence electrons in a Lewis structure?

Yes, atoms can have more than 8 valence electrons in a Lewis structure. This is known as an expanded octet and is commonly seen in elements in the third row and below on the periodic table.

3. How do atoms with more than 8 valence electrons form bonds in a Lewis structure?

In order to accommodate the extra electrons, atoms with more than 8 valence electrons can form multiple bonds, such as double or triple bonds, with other atoms. This allows for the sharing of electrons and the formation of stable molecules.

4. What determines the number of valence electrons in an atom?

The number of valence electrons in an atom is determined by its position on the periodic table. Elements in the same group or column have the same number of valence electrons, which is equal to their group number.

5. Why are Lewis structures important in chemistry?

Lewis structures are important in chemistry because they help us understand the bonding and structure of molecules, which is crucial in understanding their properties and reactivity. They also help chemists predict the behavior of molecules in different chemical reactions.

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