Question

1) How many structures are possible for a square planar molecule with a formula of AX2Y2?

2) How many structures are possible for a tetrahedral molecule with a formula of AHXYZ?

Answer 1

Only two structures are possible for a square planar molecule with a formula of AX2Y2.
Those two structures are CIS and TRANS structures.
If two groups attached to the carbons of the double bond are on the same side of the double bond, they are considered cis alkene but if they lie on opposite sides of the double bond, they are trans .
Hope it helps.