The properties of these fundamental particles are summarized in Table 2.1. The electron has a charge of 1− and is a much lighter particle with a mass of about 0.00055 amu (it would take about 1800 electrons to equal the mass of one proton). A neutron is a slightly heavier particle with a mass 1.0087 amu and a charge of zero as its name suggests, it is neutral. (The Dalton (Da) and the unified atomic mass unit (u) are alternative units that are equivalent to the amu.) The fundamental unit of charge (also called the elementary charge) equals the magnitude of the charge of an electron (e) with e = 1.602 × × 10 −19 C.Ī proton has a mass of 1.0073 amu and a charge of 1+. (This isotope is known as “carbon-12” as will be discussed later in this module.) Thus, one amu is exactly 1 12 1 12 of the mass of one carbon-12 atom: 1 amu = 1.6605 × × 10 −24 g. Since 1961, it has been defined with regard to the most abundant isotope of carbon, atoms of which are assigned masses of exactly 12 amu. The amu was originally defined based on hydrogen, the lightest element, then later in terms of oxygen. When describing the properties of tiny objects such as atoms, we use appropriately small units of measure, such as the atomic mass unit (amu) and the fundamental unit of charge (e). For example, a carbon atom weighs less than 2 × × 10 −23 g, and an electron has a charge of less than 2 × × 10 −19 C (coulomb). (credit middle: modification of work by “babyknight”/Wikimedia Commons credit right: modification of work by Paxson Woelber)Ītoms-and the protons, neutrons, and electrons that compose them-are extremely small. Figure 2.10 If an atom could be expanded to the size of a football stadium, the nucleus would be the size of a single blueberry. For a perspective about their relative sizes, consider this: If the nucleus were the size of a blueberry, the atom would be about the size of a football stadium ( Figure 2.10). The diameter of an atom is on the order of 10 −10 m, whereas the diameter of the nucleus is roughly 10 −15 m-about 100,000 times smaller. The nucleus contains the majority of an atom’s mass because protons and neutrons are much heavier than electrons, whereas electrons occupy almost all of an atom’s volume. It was learned that an atom contains a very small nucleus composed of positively charged protons and uncharged neutrons, surrounded by a much larger volume of space containing negatively charged electrons. The development of modern atomic theory revealed much about the inner structure of atoms. Calculate average atomic mass and isotopic abundance.Define the atomic mass unit and average atomic mass.Write and interpret symbols that depict the atomic number, mass number, and charge of an atom or ion.Appendix L: Standard Electrode (Half-Cell) Potentialsīy the end of this section, you will be able to:.Appendix K: Formation Constants for Complex Ions.Appendix I: Ionization Constants of Weak Bases.Appendix H: Ionization Constants of Weak Acids.Appendix G: Standard Thermodynamic Properties for Selected Substances.Appendix F: Composition of Commercial Acids and Bases.Appendix D: Fundamental Physical Constants.Appendix C: Units and Conversion Factors.
#Be atomic symbol free#
Second Law of Thermodynamics and Gibbs Free Energy.Application: Precipitation and Dissolution.Shifting Equilibria: LeChatelier’s Principle.Chemical Equilibria and Applications Toggle Dropdown Collision Theory and Factors Affecting Reaction Rates.Solutions and Colligative Properties Toggle Dropdown Liquids, Solids, and Modern Materials Toggle Dropdown Chemical Bonding and Molecular Geometry Toggle Dropdown Thermochemical Guidelines, Enthalpy of Formation and Hess's Law.Solution Stoichiometry and Combustion Analysis.Writing and Balancing Chemical Equations.Stoichiometry of Chemical Reactions Toggle Dropdown Determining Empirical and Molecular Formulas.Composition of Substances and Solutions Toggle Dropdown Molecular and Ionic Compounds and Their Nomenclature.Early Ideas and Evolution of Atomic Theory.Measurements and Uncertainty in Measurement.Classification, Physical and Chemical Properties.
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