Central Atom

[Isaac Eyler 1E]

4.7 (a) "What is the shape of the thionyl chloride molecule, SOCl2? Sulfur is the central atom."


This problem explicitly gives sulfur as the central atom; however, in this instance, is it acceptable to use Oxygen as the central atom should the problem not have specifically given the central atom? What properties am I looking for when determining the central atom, or will it always be given?

[Deap Bhandal L1 S1J]

Usually the least electronegative atom is the central atom.

[SalmaQ]

The least electronegative element tends to be the central atom when creating the lewis dot structures because they tend to be more stable this way. However, there is an exception with H2O because oxygen is more electronegative than hydrogen but in this case, oxygen is still the central atom.

[Amelia Georgius 1K]

For the most part, use the atom with the lowest electronegativity as the central atom unless the problem tells you otherwise

[Sophia Kim 1C]

The rule is generally that the most electronegative atom is the central atom since these atoms are more open to sharing electrons but in this case since sulfur is explicitly stated in the problem you would use sulfur.