This is a detailed introduction to matter, the elements of the periodic table, atoms, electrons, reactions and bonding, and radioactivity. This volume provides young adults with chemistry examples that reflect their real-world. Key terms, easy experiments, and clear illustrations guide students through subatomic explorations. A chapter about Niels Bohr and his model for the atom honors his contribution to the understanding of atomic structure. Tools and techniques, such as a scanning tunneling microscope, Rutherford's gold foil experiment, and a mass spectrometer, help readers to gain a comprehensive understanding of atoms and molecules.