Which one of the following arrangements do not give the correct picture of the trends indicated against it ?

Options

A. `F_(2) gt Cl_(2) gt Br_(2) gt I_(2)` : Bond dissociation energy
B. `F_(2) gt Cl_(2) gt Br_(2) gt I_(2)` : Electronegativity
C. `F_(2) gt Cl_(2) gt Br_(2) gt I_(2)` : Oxidizing power
D. `F_(2) gt Cl_(2) gt Br_(2) gt I_(2)` : Electron gain enthalpy

Explanation

To solve the question regarding which arrangement does not give the correct picture of the trends indicated against it, we will analyze each of the four options provided in the question.

### Step 1: Analyze Bond Dissociation Energy
- The first option is bond dissociation energy. The given order is fluorine (F2), chlorine (Cl2), bromine (Br2), and iodine (I2).
- The correct order of bond dissociation energy is Cl2 > Br2 > F2 > I2.
- This is because in fluorine, there is significant inter-electronic repulsion due to its small size, which weakens the bond. Therefore, the first arrangement is incorrect.

### Step 2: Analyze Electronegativity
- The second option is electronegativity. The given order is fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).
- This is indeed the correct order as electronegativity decreases down the group from fluorine to iodine. Fluorine is the most electronegative element, followed by chlorine, bromine, and iodine.

### Step 3: Analyze Oxidizing Property
- The third option is oxidizing property. The given order is fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).
- This is also the correct order. Fluorine is the strongest oxidizing agent, followed by chlorine, bromine, and iodine.

### Step 4: Analyze Electron Gain Enthalpy
- The fourth option is electron gain enthalpy. The given order is fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).
- The correct order of electron gain enthalpy is Cl > F > Br > I. Chlorine has a higher electron gain enthalpy than fluorine due to less electron-electron repulsion in chlorine compared to fluorine. Therefore, this arrangement is incorrect.

### Conclusion
Based on the analysis:
- The incorrect arrangement is for bond dissociation energy (Option 1) and electron gain enthalpy (Option 4). However, since the question asks for one specific arrangement that does not give the correct picture of the trends indicated against it, we can conclude that the first option regarding bond dissociation energy is the most clearly incorrect.

### Final Answer
The arrangement that does not give the correct picture of the trends indicated against it is the bond dissociation energy (F2, Cl2, Br2, I2).

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