To calculate the standard enthalpy change for the fusion reaction of a sodium atom, we need to consider the enthalpy of formation of Na g and the enthalpy of fusion of Na s .The fusion reaction can be represented as:Na s Na g The enthalpy change for this reaction is the difference between the enthalpy of formation of Na g and the enthalpy of fusion of Na s .H_fusion = H_formation Na g - H_fusion Na s Given the enthalpy of formation of Na g is 107.3 kJ/mol and the enthalpy of fusion of Na s is 2.6 kJ/mol, we can plug in the values:H_fusion = 107.3 kJ/mol - 2.6 kJ/molH_fusion = 104.7 kJ/molThe standard enthalpy change for the fusion reaction of a sodium atom is 104.7 kJ/mol.