Question

If the symbol X represents a central atom, Y represents outer atoms, and Z represents lone pairs on the central atom, the structure The central X atom is single bonded to two Y atoms, which are 180 degrees apart. The X atom has two lone pairs. could be abbreviated as XY2Z2. Classify each molecule according to its shape.Molecular Geometries: linearbent 120bent 109trigonal pyramidalT-shapedsee sawsquare planarsquare pyramidalPossiblities:XY4Z2XY5ZXY2ZXY2Z3XY4ZXY2Z2XY3Z2XY3Z

Answer 1

Answer:

XY4Z2 ----- square planar

XY5Z ------- square pyramidal

XY2Z----- bent < 120°

XY2Z3 ----- Linear

XY4Z ---- see saw

XY2Z2 ----- bent <109°

XY3Z2 ----- T shaped

XY3Z ----- Trigonal pyramidal

Explanation:

The valence shell electron pair repulsion theory ( VSEPR) gives the description of molecular geometry based on the relative number of electron pairs present in the molecule.

However, electron pairs repel each other, the repulsion between two lone pairs is greater than the repulsion between a lone pair and a bond pair which is also greater than the repulsion between two lone pairs.

The presence of lone pairs distort the bond angle and molecular geometry from the expected geometry based on VSEPR theory. Hence, in the presence of lone pairs of electron, the observed molecular geometry may be different from that predicted on the basis of the VSEPR theory, the bond angles also differ slightly or widely depending on the number of lone pairs present.

All the molecules in the question possess lone pairs, the number of electron pairs do not correspond to the observed molecular shape or geometry due to lone pair repulsion. Usually, the molecular geometry deals more with the arrangement of bonded atoms in the molecule.