Comprehensive Study Notes: Atomic Structure, Nuclear Physics, and Radiochemistry (as per transcript)

The Atom and Elements

• Atom: the smallest component of an element that can enter into chemical reactions.
• Element: a substance that cannot be separated into simpler substances by chemical means.
• Periodic Table: organizes elements; elements are the fundamental units that participate in chemical combinations.
• Atom basics: basic unit of an element that can enter into a chemical combination.
• XxYy notation and other classifications refer to compounds, complexes, molecules, molecular species, etc.
• Elemental symbol and mass/atomic numbers example: e.g., $^{35}_{17} ext{Cl}$ where mass number = p + n and atomic number Z = p.
• Mass number (A) = number of protons (Z) + number of neutrons (N). Average nucleus distance approximations (e.g., golf ball analogy) used to illustrate scale.