Which of the following subatomic particles are added or lost in order to affect the stability of an atom?

Adding or losing electrons in an atom primarily affects its stability and reactivity. Electrons are responsible for an atom's chemical properties and how it interacts with other atoms. The arrangement of electrons in energy levels or shells determines how stable an atom is. Atoms strive for a stable electron configuration, often achieved by having a full outer shell.

When an atom gains or loses electrons, it becomes an ion. A cation forms when an atom loses one or more electrons, resulting in a positive charge, while an anion forms when an atom gains electrons, leading to a negative charge. These ions exhibit different chemical behaviors compared to their neutral atom counterparts, influencing their interactions and potential reactions with other substances.

In contrast, neutrons are primarily involved in stabilizing the nucleus and influencing radioactive decay, while protons determine the elemental identity and overall charge but do not typically change to affect stability in chemical reactions. Photons, being packets of light and electromagnetic radiation, do not directly influence atomic stability or charge in the way that electrons do.