Use the image to answer the question.
The gallium in the image is melting in the person’s hand. Which changes will occur on a microscopic level?
A. The gallium atoms will gain kinetic energy.
B. The gallium atoms will gain potential energy, moving freely from each other.
C. The gallium atoms will be moving faster on average.
D. The gallium atoms will increase in temperature.
C. The gallium atoms will be moving faster on average.
The correct answer is C. The gallium atoms will be moving faster on average.
When a solid substance like gallium melts, the intermolecular forces holding the solid lattice together are overcome, allowing the atoms or molecules to move more freely from each other. As the substance melts, the atoms gain kinetic energy, causing them to vibrate and move more rapidly. Therefore, the gallium atoms in the image will be moving faster on average at a microscopic level.
Option A is incorrect because while the atoms do gain kinetic energy, they also gain potential energy as they move further from each other. Option B is incorrect because the potential energy of the gallium atoms increases as they move apart, but they also gain kinetic energy due to increased movement. Option D is incorrect because increasing in temperature is a macroscopic change that reflects the average kinetic energy of all the atoms in the substance, not a microscopic change occurring at the atomic level.