What is the electron geometry if you have 4 electron groups around the center atom?
tetrahedral
To determine the electron geometry when there are 4 electron groups around the central atom, you can use the VSEPR theory (Valence Shell Electron Pair Repulsion theory). The VSEPR theory predicts the molecular geometry of a molecule based on the repulsion between electron groups.
In this case, if you have 4 electron groups around the central atom, they can be in the form of either bonding pairs or lone pairs. The possible electronic geometries for 4 electron groups are:
1. Tetrahedral: If all 4 electron groups are bonding pairs, the electron geometry is tetrahedral. This means the molecular shape will also be tetrahedral.
2. Trigonal pyramidal: If you have three bonding pairs and one lone pair, the electron geometry is still tetrahedral, but the molecular shape becomes trigonal pyramidal. The lone pair will distort the shape.
3. Bent: If you have two bonding pairs and two lone pairs, the electron geometry is again tetrahedral, but the molecular shape becomes bent or V-shaped. The presence of lone pairs will cause the bonding pairs to push closer together, resulting in a bent shape.
Keep in mind that electron geometry refers to the arrangement of electron groups around the central atom, while molecular geometry refers to the actual shape of the molecule taking into account the presence of lone pairs as well.
To determine the electron groups and their arrangement, you will need to draw the Lewis structure of the molecule or ion, assign any remaining valence electrons, and count the total number of electron groups around the central atom.