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Lauren Bui 1E wrote:When drawing a lewis structure, how do you determine which atom goes in the center?
If you do not know the electronegativity, you can basically count how many bonds each atom can form and then decide. For example, H in CH4 can form 1 bond, so it's logical to put C in the center
This excerpt from the book helped me a bit figuring this out. "If there is doubt, a good rule of thumb for molecules other than compounds of hydrogen is to choose as the central atom the element with the lowest ionization energy. This arrangement often results in the lowest energy because an atom in the central posi- tion shares more of its electrons than does a terminal atom. Atoms with higher ionization energies are more reluctant to share and are more likely to hold on to their electrons as lone pairs.".
Arianna Perea 3H wrote:why is the central atom the one with the least electronegativity?
The least electronegative elements are in the center of lewis structures because an atom in the central position shares more of its electrons than does an atom on the sides of the central atom or the terminal position.
The central atoms should be the least electronegative atom. My TA also mentioned that if you have a molecule and its like one of an element and 4 of another then the central atom will probably be the element that only has one.
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