Which situation describes a chemical change? a. baking soda added to vinegar gives off carbon dioxide gas.

b. rubbing pencil lead onto paper changes the color of the paper.

c. chocolate changes from a solid to a liquid when heated.

d. clay pressed into a mold takes on the shape of the mold.

Which of the following statements is true about energy quantization at the atomic level? electrons in the outermost orbits are the most stable. electrons in all the orbits around the nucleus have the same amount of energy. electrons in the orbit closest to the nucleus have the least amount of energy. electrons absorb or release the same amount of energy independent of the energy levels.