What is the basis for exceptions to the aufbau principle?
electron spins are more important than energy levels in determining electron configuration.
some elements have unusual atomic orbitals.
ment
filled and half-filled energy sublevels are more stable than partially-filled energy sublevels.
electron configurations are only probable.
model

Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. in the first step, nitrogen and hydrogen react to form ammonia: (g) (g) (g) in the second step, ammonia and oxygen react to form nitric acid and water: (g) (g) (g) (g) calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. round your answer to the nearest .