In 1874, dutch chemist jacobus van’t hoff (1852–1911) and french chemist joseph le bel (1847–1930) independently deduced that a carbon atom bonded to four atoms assumes a tetrahedral geometry. prior to that time, it was believed that tetravalent carbons assumed a square planar geometry. one piece of evidence that can be used to support a tetrahedral geometry is the fact that molecules with the general formula cx2y2 (where x and y are either a hydrogen or a halogen atom) are always polar. explain how this supports a tetrahedral geometry and rules out a square planar geometry.