Among the following the species having square planar geometry for central atom are
(i) `XeF_(4),` (ii) `SF_(4)` (iii) `[NiCl_(4)]^(2-)` (iv) `[PdCl_(4)]^(2-)`

Options

A. (i) and (iv)
B. (i) and (ii)
C. (ii) and (iii)
D. (iii) and (iv)

Explanation

To determine which of the given species have square planar geometry for their central atom, we will analyze each species one by one.

### Step 1: Analyze `XeF4`
- **Valence Electrons**: Xenon (Xe) has 8 valence electrons. Each fluorine (F) contributes 1 electron, and there are 4 fluorine atoms, contributing a total of 4 electrons. Thus, the total number of valence electrons is 8 + 4 = 12.
- **Steric Number**: The steric number is calculated as the number of bonded atoms plus the number of lone pairs. In `XeF4`, there are 4 bonded fluorine atoms and 2 lone pairs on xenon. Therefore, the steric number is 4 + 2 = 6.
- **Geometry**: With a steric number of 6, the electron geometry is octahedral. However, due to the presence of 2 lone pairs, the molecular geometry is square planar.

**Conclusion**: `XeF4` has square planar geometry.

### Step 2: Analyze `SF4`
- **Valence Electrons**: Sulfur (S) has 6 valence electrons, and each fluorine contributes 1 electron. Thus, for `SF4`, the total number of valence electrons is 6 + 4 = 10.
- **Steric Number**: In `SF4`, there are 4 bonded fluorine atoms and 1 lone pair on sulfur. Therefore, the steric number is 4 + 1 = 5.
- **Geometry**: With a steric number of 5, the electron geometry is trigonal bipyramidal. The presence of a lone pair results in a seesaw molecular geometry.

**Conclusion**: `SF4` does not have square planar geometry.

### Step 3: Analyze `[NiCl4]^(2-)`
- **Valence Electrons**: Nickel (Ni) has 10 valence electrons (as it is in the 3d block), and each chlorine contributes 1 electron. Thus, for `[NiCl4]^(2-)`, the total number of valence electrons is 10 + 4 = 14.
- **Steric Number**: In `[NiCl4]^(2-)`, there are 4 bonded chlorine atoms and no lone pairs on nickel. Therefore, the steric number is 4 + 0 = 4.
- **Geometry**: With a steric number of 4, the geometry is tetrahedral.

**Conclusion**: `[NiCl4]^(2-)` does not have square planar geometry.

### Step 4: Analyze `[PdCl4]^(2-)`
- **Valence Electrons**: Palladium (Pd) has 10 valence electrons, and each chlorine contributes 1 electron. Thus, for `[PdCl4]^(2-)`, the total number of valence electrons is 10 + 4 = 14.
- **Steric Number**: In `[PdCl4]^(2-)`, there are 4 bonded chlorine atoms and no lone pairs on palladium. Therefore, the steric number is 4 + 0 = 4.
- **Geometry**: Palladium is a transition metal and, in this case, the weak field ligand (Cl) acts as a strong field ligand due to the nature of the transition metal. This results in a square planar geometry.

**Conclusion**: `[PdCl4]^(2-)` has square planar geometry.

### Final Answer
The species having square planar geometry for the central atom are:
- (i) `XeF4`
- (iv) `[PdCl4]^(2-)`