If the center atom has three groups of electrons around it, what type of electron geometry is present?

Trigonal planar

Explanation:

Trigonal planar - it is referred to the molecular shape of atom in which three bonds exist around any central atom. As there is no lone pair at the center hence all three atoms have taken the form of a triangle. All three atom lies at same plane and known as peripheral atoms

The angle between all the three atoms is 120 degree