Final answer:
The AX₄E molecular shape is called a seesaw, which comes from a trigonal bipyramidal structure with a lone pair at an equatorial position, leading to axial angles of about 173° and equatorial angles of 120°.
Step-by-step explanation:
The molecule with the formula AX₄E represents a seesaw molecular shape, which is derived from a trigonal bipyramidal geometry with one equatorial position occupied by a lone pair of electrons. The removal of one atom from the equatorial position of a trigonal bipyramid leads to the seesaw shape. In this structure, the angles between the axial positions (“Faxial-S-Faxial”) are about 173°, which is slightly less than 180° due to the presence of the lone pair causing electron repulsion. The equatorial atoms (those in the plane of the triangle), on the other hand, are spaced at 120° apart, while those in the axial positions (above or below the plane of the triangle) are at 90° relative to the equatorial plane.