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- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/04%3A_Atomic_Structure/4.06%3A_Dalton's_Atomic_TheoryThis page outlines the evolution of scientific thought on matter's composition, highlighting the debates preceding the 19th century. It emphasizes John Dalton's advancements in atomic theory, which po...This page outlines the evolution of scientific thought on matter's composition, highlighting the debates preceding the 19th century. It emphasizes John Dalton's advancements in atomic theory, which posited that matter is made of indivisible atoms and that atoms of the same element are identical. Dalton's 1804 theory established foundational principles for modern chemistry, although some aspects, like atomic indivisibility, have been updated.
- https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Descriptive_Chemistry/Periodic_Trends_of_Elemental_Properties/The_Periodic_LawThe periodic law was developed independently by Dmitri Mendeleev and Lothar Meyer in 1869. Mendeleev created the first periodic table and was shortly followed by Meyer. They both arranged the elements...The periodic law was developed independently by Dmitri Mendeleev and Lothar Meyer in 1869. Mendeleev created the first periodic table and was shortly followed by Meyer. They both arranged the elements by their mass and proposed that certain properties periodically reoccur. Meyer formed his periodic law based on the atomic volume or molar volume, which is the atomic mass divided by the density in solid form.
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/11%3A_Chemical_Reactions/11.03%3A_Balancing_EquationsThis page explains how to balance chemical equations, focusing on the law of conservation of mass, which requires equal numbers of atoms on both sides of a reaction. It offers guidelines for writing a...This page explains how to balance chemical equations, focusing on the law of conservation of mass, which requires equal numbers of atoms on both sides of a reaction. It offers guidelines for writing and balancing equations, emphasizing the importance of correct formulas, atom counting, and using the lowest coefficient ratios. An example of balancing the reaction between lead(II) nitrate and sodium chloride is provided to illustrate the process.
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/24%3A_Nuclear_Chemistry/24.01%3A_Discovery_of_RadioactivityThis page highlights the importance of the radioactive danger symbol in nuclear medicine, representing the use of radioactive materials in diagnosis and treatment. It outlines the historical evolution...This page highlights the importance of the radioactive danger symbol in nuclear medicine, representing the use of radioactive materials in diagnosis and treatment. It outlines the historical evolution of radioactivity studies, beginning with John Dalton's atomic theory, progressing through milestones by figures like Francis Aston, Henri Becquerel, and the Curies, who introduced the term "radioactivity.
- https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Instrumental_Analysis_(LibreTexts)/11%3A_Atomic_Mass_Spectrometry/11.01%3A_General_Features_of_Atomic_Mass_SpectrometryIn mass spectrometry we convert the analyte into ions and then separate these ions based on the ratio of their masses to their charges. In this section we give careful attention to what we mean by mas...In mass spectrometry we convert the analyte into ions and then separate these ions based on the ratio of their masses to their charges. In this section we give careful attention to what we mean by mass, by charge, and by mass-to-charge ratio. We also give brief consideration to how we generate and measure ions, topics covered in greater detail in subsequent sections.
- https://chem.libretexts.org/Courses/Bennington_College/Chemistry_-_An_Integrated_Approach_(Bullock)/03%3A_Why_Do_Molecules_Exist/3.01%3A_Building_BlocksAn introduction to Dalton's atomic theory and its historical context and foundations. A brief discussion on the relationships between atoms, elements, molecules and compounds.
