Final answer:
The question focuses on classifying particles such as protons, neutrons, electrons, and X-rays by their properties. Protons and neutrons have a mass number of 1, but electrons and X-rays have a mass number of 0, which signifies they lack nucleons. This categorization is crucial in understanding particle behavior and interactions with matter.
Step-by-step explanation:
The question pertains to the categorization of particles in terms of their respective properties, such as mass number (A), atomic number (Z), and charge. When considering a proton, A = 1 because it is made up of one nucleon (itself); Z = +1 due to its positive charge. Neutrons also have A = 1 because they are single nucleons, but Z = 0 because they are neutral (no charge). Electrons have a negative charge, so Z = −1, and because they contain no nucleons, A = 0.
X-rays and gamma rays are forms of high-energy electromagnetic radiation; they have no rest mass (nucleons), so both A and Z are 0. It's important to note that alpha particles are equivalent to helium nuclei with two protons and two neutrons (A = 4, Z = +2), beta particles (β particles) are high-speed electrons with A = 0 and Z = −1, and gamma rays have even higher energy than X-rays but both fall under the category of electromagnetic radiation with no mass number or atomic number.
These particles interact with matter in various ways as demonstrated in the provided diagram, showing alpha particles being stopped by paper, beta particles penetrating paper but not thick materials, and gamma rays requiring dense materials like lead to be halted.