Central Atom

[Karina Vasquez 1D]

Can fluorine, chlorine, or any atom in group 17 ever be the central atom? Is it just fluorine that can't be a central atom?

[Leah farhadi 1F]

I think there are examples were chlorine is in the center of the lewis structure, i.e. ClH4 were Cl will be in the middle surrounded by hydrogen. However, in most examples I have seen fluorine has not been the central atom. I think this has to do with reasoning that Cl and F only need one more valence electron to achieve in octet.

[Kevin To 1B]

The central atom is essentially required to form at least one bond, other than H and F. Nonetheless, some chemicals do have other halogen atoms as the central atom, such as perchlorate (ClO₄^-), depending on the conditions.

[Radha Patel 4I]

The central atom is restricted to the element that has the lowest ionization energy. Fluorine (as far as I know) has the highest ionization energy, so whatever element that has a higher ionization energy than Fluorine would allow Fluorine to be the central atom.

[BCaballero_4F]

The central atom has to be the atom with the lowest ionization energy, so I think those can be in the middle if they have a lower ionization energy than other atoms involved.

[Verity Lai 2K]

Usually the center atom is the one with the most unpaired electrons in the valence shell because then they can make more bonds and it's just easier for drawing the lewis structure.

[Miriam Villarreal 1J]

The central atom is usually the one with the element of lowest electronegativity, and halogens and hydrogen are usually terminal meaning the surrounding that you might have multiple of.

[Kaitlyn Ang 1J]

Also, in general, if there is a problem that asks you to draw the Lewis Structure for a molecule, the element in the middle of the molecular formula normally actually IS the element in the middle. Of course, this doesn't work all the time, and that's where checking electronegativity is important, but if you're looking for a shortcut, there it is :)