To calculate the standard enthalpy of formation (deltaH°f) for atomic oxygen (O(g)), one should consider the bond energy of O2(g), which is 142.0 kJ/mol. Since the formation of one mole of O(g) from O2(g) involves breaking the O=O bond, the deltaH°f for O(g) can be determined by halving the bond energy of O2. This approach is based on the principle that breaking a bond requires energy input, thus reflecting the enthalpy change. The calculation yields a deltaH°f of 71.0 kJ/mol for O(g). This method effectively addresses the problem of finding the enthalpy for the formation of a single oxygen atom.