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Chemistry LibreTexts

2: Elements, Atoms, and the Periodic Table

  • Page ID
    15921
  • Just as a language has an alphabet from which words are built, chemistry has an alphabet from which matter is described. However, the chemical alphabet is larger than the one we use for spelling. You may have already figured out that the chemical alphabet consists of the chemical elements. Their role is central to chemistry, for they combine to form the millions and millions of known compounds.

    • 2.0: Prelude to Elements, Atoms, and the Periodic Table
      The hardest material in the human body is tooth enamel. It has to be hard so that our teeth can serve us for a lifetime of biting and chewing; however, tough as it is, tooth enamel is susceptible to chemical attack. Acids found in some foods or made by bacteria that feed on food residues on our teeth are capable of dissolving enamel. Unprotected by enamel, a tooth will start to decay, thus developing cavities and other dental problems.
    • 2.1: The Elements
      All matter is composed of elements. Chemical elements are represented by a one- or two-letter symbol.
    • 2.2: Atomic Theory
      Atoms are the ultimate building blocks of all matter. The modern atomic theory establishes the concepts of atoms and how they compose matter.
    • 2.3: The Structure of Atoms
      Atoms are composed of three main subatomic particles: protons, neutrons, and electrons. Protons and neutrons are grouped together in the nucleus of an atom, while electrons orbit about the nucleus.
    • 2.4: Nuclei of Atoms
      Elements can be identified by their atomic number and mass number. Isotopes are atoms of the same element that have different masses.
    • 2.5: Atomic Masses
      Atoms have a mass that is based largely on the number of protons and neutrons in their nucleus.
    • 2.6: Arrangements of Electrons
      Electrons are organized into shells and subshells about the nucleus of an atom.
    • 2.7: The Periodic Table
      The chemical elements are arranged in a chart called the periodic table. Some characteristics of the elements are related to their position on the periodic table.
    • 2.E: Elements, Atoms, and the Periodic Table (Exercises)
      These are homework exercises to accompany Chapter 2 of the Ball et al. "The Basics of GOB Chemistry" Textmap.
    • 2.S: Elements, Atoms, and the Periodic Table (Summary)
      To ensure that you understand the material in this chapter, you should review the meanings of the following bold terms and ask yourself how they relate to the topics in the chapter.