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Placement

Posted: Sat Oct 28, 2017 11:21 pm
by Mary Becerra 2D
When constructing Lewis structures, how do you know which element to put in the middle?

Re: Placement

Posted: Sat Oct 28, 2017 11:37 pm
by Kaylin Krahn 1I
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.

Re: Placement

Posted: Sun Oct 29, 2017 8:13 pm
by Bansi Amin 1D
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.

Re: Placement  [ENDORSED]

Posted: Sun Oct 29, 2017 9:05 pm
by Katherine Jordak 1H
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.

Re: Placement

Posted: Sun Oct 29, 2017 9:07 pm
by Katherine Jordak 1H
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.

Re: Placement

Posted: Sun Oct 29, 2017 9:36 pm
by Emily Oren 3C
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?

Re: Placement

Posted: Sun Oct 29, 2017 9:48 pm
by Jessica Schirmer 1J
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.