That’s when the arrived. The Electron Geometry is the ghostly, invisible blueprint of a molecule—it cares only about regions of negative charge . It doesn’t care if you are a lonely pair of electrons or a bonded pair; it just counts how many "clouds" are pushing against each other.
But here was the twist. Because the ion had a ( 2- ) charge, the Oxygens were slightly jealous—they wanted even more negative attention. So they began to delocalize . The double bonds started switching places so fast that, if you looked at the molecule, every bond looked identical: 1.5 bonds (a resonance hybrid). so4 2 electron geometry and molecular geometry
"Since all four electron regions contain atoms," declared the Molecular Geometry, "your visible shape is... ." That’s when the arrived
The four Oxygens stood at the corners of a tetrahedron, repelling each other equally. The molecule was symmetric, stable, and perfectly non-polar in its charge distribution, despite carrying a net negative charge. But here was the twist
"Four regions," whispered the ghost of Electron Geometry. "That means I must arrange you in . 109.5 degrees apart. This is the most comfortable way for four clouds to sleep in the same bed."
He formed four double bonds (S=O). But to the Electron Geometry, those double bonds count as just of electron density each. So, looking at the electron clouds only: Sulfur had four regions of high electron density pushing away from him.
Sulfur made a decision. He would use his d-orbital expansion. He promoted one of his 3s electrons to a higher energy level, creating six unpaired electrons. Then, he borrowed two extra electrons from the universe (giving the ion its ( 2- ) charge). Now, with eight electrons to allocate, he invited the four Oxygens to bond.