Identify the correct order of standard enthalpy of formation of sodium halides.

Question

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Strategy:
 The enthalpy of formation for ionic halides depends on the lattice energy and the bond energy of the halogen. Smaller anions result in stronger lattice forces and more exothermic (negative) formation energies.

Step 1: Analyze enthalpy of formation () trends
The formation of sodium halides follow the trend of anion size: .
Smaller ion (Fluoride) produces the most stable salt with higher lattice energy.
Values (approx kJ/mol):
- :  (Most negative)
- : 
- : 
- :  (Least negative)

Step

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