The correct answer is NH3 - Pyramidal and BF3 - Planar Explanation & Key Takeaways: NH3 • There are three single bonds and one lone pair of electrons in the NH3 molecule. • It has a molecular geometry of trigonal pyramidal which also looks like a distorted tetrahedral structure. • The shape is distorted because of the lone pairs of electrons. • This pair exerts repulsive forces on the bonding pairs of electrons. • Although the bond angle should be 109.5 degrees for trigonal pyramidal molecular geometry, it decreases to 107 degrees due to the lone pair on the nitrogen atom. BF3 • Boron trifluoride is an inorganic compound with the formula BF3. • This pungent colorless toxic gas forms white fumes in moist air. • It is a useful Lewis acid and a versatile building block for other boron compounds. • It has a molecular geometry of trigonal planar. • Trigonal planar is a molecular geometry model with one atom at the center and three atoms at the corners of an equilateral triangle, called peripheral atoms, all in one plane. • In an ideal trigonal planar species, all three ligands are identical and all bond angles are 120°. The below-mentioned table tells about the shape and bond angle of the compounds mentioned: +----------+----------------------------------------------+------------+--------------------+ | Molecule | Total Electron Pairs (Bond Pair + Lone Pair) | Bond Angle | Shape | +----------+----------------------------------------------+------------+--------------------+ | NH 3 | 4 = 3 + 1 | 107.5° | Trigonal Pyramidal | | H 2 O | 4 = 2 + 2 | 104.5° | Bent or V-shaped | | BF 3 | 3 = 3 + 0 | 120° | Trigonal Planar | | BeCl 2 | 2 = 2 + 0 | 180° | Linear | +----------+----------------------------------------------+------------+--------------------+