Alpha particles (α) are characterized by what property?

Alpha particles are indeed characterized by a positive charge and low penetrating ability. Being composed of two protons and two neutrons, they carry a significant positive charge. This defining feature is crucial when understanding their interaction with other matter.

The low penetrating ability of alpha particles stems from their relatively large mass compared to other forms of radiation, such as beta particles and gamma rays. Because of this larger mass, alpha particles interact more readily with matter, losing their energy quickly and being easily absorbed by materials such as paper or skin. This characteristic is important in understanding alpha particles' behavior in different environments and their implications for safety, as they are generally not able to penetrate the outer layers of the human body.

In contrast, other options present properties that do not align with the characteristics of alpha particles. Therefore, recognizing both the charge and penetrating ability gives a clearer picture of alpha particles and their behavior in the context of radiation and chemistry.