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Homework problem 3.57

Posted: Sun Nov 05, 2017 11:47 am
by Tasnia Haider 1E
In all of the Lewis structures, the highest ionization energy atoms are the central atoms, even though we learned that the central atom should have the lowest ionization energy. Why is it like that? Is it only to show the resonance structures?

Re: Homework problem 3.57

Posted: Sun Nov 05, 2017 1:33 pm
by Rachel Formaker 1E
The atom in the center in the molecules here is always the one with the lowest ionization energy, so these do follow the guideline laid out in class.

The guideline for ionization energies is that ionization energy decreases as you go down a group and increases right to left across a period.

In the sulfite ion, sulfur has a lower ionization energy that oxygen, which is expected since it is right below oxygen.
Hydrogen sulfite follows the same rules as sulfite, because hydrogen will never be the central atom since it can only form 2 bonds.
In the perchlorate ion, chlorine actually has a slightly lower ionization energy than oxygen, although they are very close.
In the nitrite ion, nitrogen has a lower ionization energy than oxygen because it is to the left of oxygen.

For a refresher on ionization energies, take a look at the figure on page 54 of the textbook.