Which of the following statements is true about energy quantization at the atomic level?
electrons can be present at any location inside the electron cloud.
electrons are present in distinct energy levels around the nucleus.
electrons are present in the free space in between two energy levels.
electrons prefer to be present as far away from the nucleus as possible.

Electrons are present in distinct energy levels around the nucleus.

Explanation:

just took the test as well

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.