Final answer:
An electron in the third energy shell has more potential energy than an electron in the first energy shell because it is further from the nucleus and thus less tightly bound by the nucleus's electrostatic attraction. This means it would take more energy to move an electron to this shell or be released if the electron dropped to a lower shell.
Step-by-step explanation:
An electron in the third energy shell has more potential energy than an electron in the first energy shell. This is because electrons in higher energy shells are further away from the nucleus, and the increased distance means that the electrostatic attraction between the nucleus and the electron is weaker. As a result, it takes more energy to add an electron to a higher shell, and similarly, an electron in a higher energy shell would release more energy when it falls to a lower energy state.
When an electron absorbs energy, such as from a photon of light, it can be excited to move faster and relocate to a more distant shell. This elevated state is unstable, and the electron tends to release energy and fall back to a lower energy shell. Thus, electrons in higher shells carry more potential energy and are less stable compared to those in lower shells.