Which of the following complex compounds will exhibit highest magnetic behaviour ?
`(At.No. Ti = 22, Cr = 24, Co = 27, Zn = 30)`

Options

A. `[Zn(NH_(3))_(6)]^(2+)`
B. `[Ti(NH_(3))_(6)]^(3+)`
C. `[Cr (NH_(3))_(6)]^(3+)`
D. `[Co (NH_(3))_(6)]^(3+)`

Explanation

To determine which of the given complex compounds exhibits the highest magnetic behavior, we need to analyze the oxidation states of the central metal ions and the electronic configurations of these metal ions in their respective complexes.

### Step-by-Step Solution:

1. **Identify the Complexes:**
- A) Zn(NH3)6^2+
- B) Ti(NH3)6^3+
- C) Cr(NH3)6^3+
- D) Co(NH3)6^3+

2. **Determine the Oxidation States:**
- For Zn in Zn(NH3)6^2+, the oxidation state is +2.
- For Ti in Ti(NH3)6^3+, the oxidation state is +3.
- For Cr in Cr(NH3)6^3+, the oxidation state is +3.
- For Co in Co(NH3)6^3+, the oxidation state is +3.

3. **Analyze the Behavior of Ammonia as a Ligand:**
- Ammonia (NH3) acts as a weak field ligand in the presence of +2 oxidation states and as a strong field ligand in the presence of +3 oxidation states.
- Therefore:
- In Zn(NH3)6^2+, NH3 is a weak field ligand.
- In Ti(NH3)6^3+, Cr(NH3)6^3+, and Co(NH3)6^3+, NH3 is a strong field ligand.

4. **Determine the Electronic Configurations:**
- **Zn^2+ (Atomic number 30):** Configuration = [Ar] 3d^10. (Diamagnetic, no unpaired electrons)
- **Ti^3+ (Atomic number 22):** Configuration = [Ar] 3d^1. (1 unpaired electron)
- **Cr^3+ (Atomic number 24):** Configuration = [Ar] 3d^3. (3 unpaired electrons)
- **Co^3+ (Atomic number 27):** Configuration = [Ar] 3d^6. (In a strong field, it will pair up, resulting in no unpaired electrons)

5. **Count the Unpaired Electrons:**
- Zn(NH3)6^2+: 0 unpaired electrons (Diamagnetic)
- Ti(NH3)6^3+: 1 unpaired electron
- Cr(NH3)6^3+: 3 unpaired electrons
- Co(NH3)6^3+: 0 unpaired electrons (Diamagnetic)

6. **Determine the Magnetic Behavior:**
- The magnetic behavior of a complex is directly related to the number of unpaired electrons.
- Cr(NH3)6^3+ has the highest number of unpaired electrons (3), making it exhibit the highest magnetic behavior.

### Conclusion:
The complex that exhibits the highest magnetic behavior is **Cr(NH3)6^3+** due to the presence of 3 unpaired electrons.