(Tro's 'electron groups') instead of electron pair in determining a value for SN. Or triple-bonded to the central atom, we sometimes use the term electron domain Since we end up counting a bonded atom only once, even if it is double.
Tro's text refers to this count, what we are calling steric number, The number of lone pairs present on the central atom.
This amounts simply to a count of the number of bonded atoms plus Number (abbreviated SN) for the central atom of a molecular structure. To do this, we apply the valence shell electron pair repulsion or VSEPR model.
Shape of the molecule, or its three-dimensional structure. Molecular structure: The five basic shapesįor simple molecules, we can use them to predict the Single-central atom structures: The five basic shapes. GENERAL CHEMISTRY TOPICS Molecular structure