Enthalpy change of atomisation of IodineWatch
1⁄2 I2(s) ----> I(g)
Why is 1⁄2 I2 solid and not gaseous?
I believe this is to do with the Maxwell-Boltzman distribution. For a given number of particles in 1/2 I2 (s), some particles will have enough activation energy so the reaction can occur. Enthalpy of atomisation is defined as the amount of energy required for a substance in standard conditions to form one mole of gaseous atoms. As all of the bonds are broken but none are formed, the value is always positive, so energy is required to be inputted into the system, which comes as heat.