Question

Part A:

What is the molecular geometry of amolecule with 4 outer atoms and 1 lone pair on the centralatom?

Part B:

What is the molecular geometry of a moleculewith 2 outer atoms and 2 lone pairs on the central atom?

Part C: 

What is the molecular geometry of amolecule with 4 outer atoms and 2 lone pairs on the centralatom?

Answer 1

Number of bonding groups              Electron group arrangements
    2                                                  Linear
    3                                                  Trigonal Planar
    4                                                  Tetrahedral
    5                                                  Trigonal Bipyramidal
    6                                                  Octahedral

However, for the molecular geometry:
    AX_mE_n, where A=centralatom, X_m=surrounding atom, E_n=non-bondingvalence electron groups
AX₂E/AX₂E₂: bent (or angular)
AX₃E: trigonal pyramidal
AX₄E: seesaw
AX₃E₂: T-shaped
AX₂E₃: linear
AX₅E: square pyramidal
AX₄E₂: square planar

A) 4 outer atoms & 1 lone pair = AX₄E = seesaw
B) 2 outer atoms & 2 lone pairs = AX₂E₂ =bent/angular
C) 4 outer atoms & 2 lone pairs = AX₄E₂ =square planar

Hope this helps! :)