Before identifying geometry, we must look at the electron count. For the sulfate ion: 6 valence electrons Oxygen (O): 6 valence electrons 4 = 24 electrons Negative Charge (2-): +2 electrons Total Valence Electrons: 32

Sulfur nodded. He arranged his four double bonds like the corners of a pyramid.

"No lone pairs to hide," Sulfur said. "What you see is what you get."

When a central atom has four electron groups, they push away from each other to be as far apart as possible. This results in an Electron Geometry of Tetrahedral . 3. Molecular Geometry of SO42−cap S cap O sub 4 raised to the 2 minus power

Deep in the valley of the Periodic Table lived a large, charismatic atom named Sulfur. Sulfur was unique. Unlike his neighbor, the rigid Carbon, Sulfur had an expanded wardrobe—empty d-orbitals that allowed him to dress up in more than eight electrons. Today, Sulfur faced a dilemma. He had four Oxygen atoms asking for his attention. Each Oxygen needed two electrons to complete its own valence shell.

$6 + 24 + 2 = 32$ electrons.

Electron geometry describes the spatial arrangement of all electron domains around the central atom, including both bonding pairs and lone pairs.

And so, in the lake of an acid mine or the ocean of a cell, every ( \textSO_4^2- ) ion sits quietly, a perfect tetrahedral gem, stable and unbothered—because it knew how to count its regions and share its charge.

In a perfect tetrahedral arrangement, the bond angles are exactly 109.5° .