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- https://chem.libretexts.org/Courses/University_of_California_Irvine/UCI%3A_General_Chemistry_1A_(OpenChem)/185Isotopes_Natural_Abundance_and_Molecular_Mass_(OpenChem)
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/04%3A_Atomic_StructureThis page details the evolution of atomic theory from ancient Greece to modern science, contrasting Democritus's indivisible atoms with Aristotle's divisible matter. It discusses fundamental laws of c...This page details the evolution of atomic theory from ancient Greece to modern science, contrasting Democritus's indivisible atoms with Aristotle's divisible matter. It discusses fundamental laws of chemistry, like conservation of mass, and pivotal experiments such as Rutherford's gold foil and J.J. Thomson's cathode ray tube that reveal atomic structure.
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/04%3A_Atomic_Structure/4.19%3A_Atomic_Mass_UnitThis page highlights the historical importance of standardized measurements in the U.S., particularly in science for consistent data comparison. It establishes the carbon-12 atom as the reference for ...This page highlights the historical importance of standardized measurements in the U.S., particularly in science for consistent data comparison. It establishes the carbon-12 atom as the reference for atomic mass, defining one atomic mass unit as one twelfth of carbon-12's mass. The variations in atomic masses, such as oxygen-16, are discussed due to nucleus interactions, and a mass spectrometer is identified as the tool for measuring these atomic masses.
- https://chem.libretexts.org/Bookshelves/General_Chemistry/General_Chemistry_Supplement_(Eames)/Chemistry_Basics/Discovering_Sub-atomic_ParticlesThe ray that comes out of the cathode is the same whatever the material, and he found that you can generate the same particle by heating metal filaments very hot or exposing a metal surface to UV ligh...The ray that comes out of the cathode is the same whatever the material, and he found that you can generate the same particle by heating metal filaments very hot or exposing a metal surface to UV light (the light that gives you sunburns). Moseley's work showed that the ordering of the periodic table is based on the atomic number, which is the number of positive charges in the nucleus and also the number of electrons.
- https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Physical_Chemistry_(LibreTexts)/14%3A_Nuclear_Magnetic_Resonance_Spectroscopy/14.06%3A_Spin-Spin_Coupling_Can_Lead_to_Multiplets_in_NMR_SpectraThis page explains spin-spin coupling in NMR spectroscopy, detailing how proton signals split into sub-peaks based on magnetic interactions between non-equivalent nuclei, following the n + 1 rule. It ...This page explains spin-spin coupling in NMR spectroscopy, detailing how proton signals split into sub-peaks based on magnetic interactions between non-equivalent nuclei, following the n + 1 rule. It covers coupling constants for protons on sp3 and sp2 carbons and introduces complex coupling scenarios with multiple interacting proton sets.
- https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Physical_Chemistry_(LibreTexts)/09%3A_Chemical_Bonding_in_Diatomic_Molecules/9.04%3A_Chemical_Bond_StabilityThis page details the calculation of molecular orbital energies for H+2 using the Linear Combination of Atomic Orbitals method. It explains key components like Coulomb, exchange, and over...This page details the calculation of molecular orbital energies for H+2 using the Linear Combination of Atomic Orbitals method. It explains key components like Coulomb, exchange, and overlap integrals, and their roles in energy equations. The text highlights the contributions of proton repulsion and electron distribution to total energy, along with defining the Coulomb and exchange integrals.
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/06%3A_The_Periodic_Table/6.18%3A_Electron_ShieldingThis page discusses roller derby, where a jammer scores points by passing opponents while blockers try to stop them. It also explains electron shielding in atoms, detailing how inner electrons affect ...This page discusses roller derby, where a jammer scores points by passing opponents while blockers try to stop them. It also explains electron shielding in atoms, detailing how inner electrons affect attraction to outer electrons and influence ionization energy, with examples from lithium and aluminum, as well as variations in ionization energy across groups 13-15 and 15-16, highlighting the effects of electron configuration and pairing.
- https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Analytical_Chemistry_2.1_(Harvey)/13%3A_Kinetic_Methods/13.03%3A_RadiochemistryThis page explains the concept of isotopes, which are elements with the same number of protons but different numbers of neutrons, and their applications in radioactive decay analysis. It describes the...This page explains the concept of isotopes, which are elements with the same number of protons but different numbers of neutrons, and their applications in radioactive decay analysis. It describes the types of radioactive decay particles (alpha, beta, gamma rays, and X-rays) and the role of isotopes in identifying nuclear stability. It also covers the mathematical models for radioactive decay, including first-order kinetics and half-life calculations.
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/06%3A_The_Periodic_Table/6.17%3A_Periodic_Trends_-_Ionization_EnergyThis page discusses two topics: sheep behavior, highlighting their tendency to herd influenced by attraction and external factors, and the concept of ionization energy in chemistry, explaining how it ...This page discusses two topics: sheep behavior, highlighting their tendency to herd influenced by attraction and external factors, and the concept of ionization energy in chemistry, explaining how it varies across periods and groups in the periodic table due to nuclear attraction and atomic size. Understanding these trends is essential for predicting atomic behavior.
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/06%3A_The_Periodic_Table/6.20%3A_Periodic_Trends_-_Ionic_RadiiThis page discusses the sale of shelled peanuts for snacking or cooking and explains ionic radius, detailing how ion sizes vary with electron loss or gain. Cations become smaller when electrons are re...This page discusses the sale of shelled peanuts for snacking or cooking and explains ionic radius, detailing how ion sizes vary with electron loss or gain. Cations become smaller when electrons are removed due to reduced energy levels and a higher proton-electron ratio, while anions grow larger with added electrons due to increased repulsion. It notes that ionic radius measurements often utilize crystal lattice structures, with differences stemming from the measurement techniques used.
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/04%3A_Atomic_Structure/4.07%3A_AtomThis page explains that atoms are the smallest particles of an element, consisting of protons, neutrons, and electrons. Each element has a unique number of protons, and atoms are electrically neutral ...This page explains that atoms are the smallest particles of an element, consisting of protons, neutrons, and electrons. Each element has a unique number of protons, and atoms are electrically neutral due to the equal number of protons and electrons. Although they are generally small, their sizes differ among elements. The helium atom model is used to illustrate the basic atomic structure, featuring a nucleus of protons and neutrons, with electrons orbiting around it.
