Why NF3 is stable while NCl3 and NI3 is explosiv?

 In NF3 molecule nitrogen is in +3 oxidation state and the fluorin atom is in -1 oxidation state.  

 We know according to the pouling scale  of  electronegativity the most electronegative atom is fluorine that is 4 .  

 The -1 oxidation state  of      halogens  is stable as present in NF3.  On the other hand NCl3 and NI3  chlorine and iodine is present as +1 oxidation state and nitrogen is in +3 oxidation state. 

 The +1 oxidation state of halogens is  good oxidizing agent . it can oxidize nitrogen into N2 gases and itselfe Cl2 and I2 gases which is also more stable   thats why NCl3 and NI3 is explosive.