Placement  [ENDORSED]

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Mary Becerra 2D
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Joined: Fri Sep 29, 2017 7:06 am

Placement

Postby Mary Becerra 2D » Sat Oct 28, 2017 11:21 pm

When constructing Lewis structures, how do you know which element to put in the middle?

Kaylin Krahn 1I
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Re: Placement

Postby Kaylin Krahn 1I » Sat Oct 28, 2017 11:37 pm

The central atom tends to be the one with lower ionization energy or the least electronegativity, so you would have to know the trends of the periodic table.

Bansi Amin 1D
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Re: Placement

Postby Bansi Amin 1D » Sun Oct 29, 2017 8:13 pm

The central atom is the one with the lowest ionization energy. Ionization energy increases from left to right and decreases from top to bottom. The central atom must be the one with the least ionization energy because it can form more bonds than the other element due to the lower ionization energy.

Katherine Jordak 1H
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Joined: Fri Sep 29, 2017 7:05 am

Re: Placement  [ENDORSED]

Postby Katherine Jordak 1H » Sun Oct 29, 2017 9:05 pm

The central atom is the atom with the lowest ionization energy, yes. That means it is usually the atom that is closest to having its outer orbitals half-filled (so there is plenty of space for bonds). If two atoms in the same compound are in the same family on the periodic table, then the lower one is the central atom. Because of shielding, the lower atom will have a lower ionization energy.

Katherine Jordak 1H
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Joined: Fri Sep 29, 2017 7:05 am

Re: Placement

Postby Katherine Jordak 1H » Sun Oct 29, 2017 9:07 pm

The central atom is the atom with the lowest ionization energy, yes. That means it is usually the atom that is closest to having its outer orbitals half-filled (so there is plenty of space for bonds). If two atoms in the same compound are in the same family on the periodic table, then the lower one is the central atom. Because of shielding, the lower atom will have a lower ionization energy.

Emily Oren 3C
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

Re: Placement

Postby Emily Oren 3C » Sun Oct 29, 2017 9:36 pm

What if there are multiple of the atom with the lowest ionization energy (for example 4 carbon atoms)? Which one would be central and how would they be arranged? Can we predict the shape of the Lewis structures for complicated molecules?

Jessica Schirmer 1J
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Joined: Fri Sep 29, 2017 7:04 am

Re: Placement

Postby Jessica Schirmer 1J » Sun Oct 29, 2017 9:48 pm

There are usually patterns with finding the central atom as well. I noticed that the more problems I completed that I found many similarities between different molecules.


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