Will the following reaction occur spontaneously at 25°C? Justify your answer. 3 O2(g) → 2 O3(g)
∆H°rxn = 285 kJ/mol ∆S°rxn = −137 J/mol·K

In 1909 Ernest Rutherford designed an experiment to test the plum pudding model. In the experiment, positively charged alpha particles were fired at thin gold foil. Most alpha particles went straight through the foil. This evidence led Rutherford to suggest a new model for the atom, called the nuclear model