Final answer:
The difference between atom A and atom B would be the energy state of the outermost electron, either moving to a lower or higher energy state, not the loss or gain of electrons to form ions.
Step-by-step explanation:
The key difference between atom A and atom B lies in the energy state of their outermost electrons. When comparing the electron arrangements of neutral atoms, one must look at the energy states of the electrons to determine any changes. If atom B's outer electron moves to a lower energy state, it means energy has been released and the electron has transitioned from an excited state to a more stable, ground state. On the other hand, if the electron moves to a higher energy state, it indicates that the electron has absorbed energy and is now in an excited state.
In this context, the choice that most accurately reflects atom B's change would either be (b) or (c), depending on whether the electron is moving to a lower or higher energy level, respectively. The loss or gain of electrons would result in the formation of ions, which isn't indicated in the question for atom B.