Chapter 5. Introductory Atomic Theory and Structure

Enhanced Introductory College Chemistry

by Gregory Anderson; Caryn Fahey; Jackie MacDonald; Adrienne Richards; Samantha Sullivan Sauer; J.R. van Haarlem; and  David Wegman;

Chapter Contents

Except where otherwise noted, this OER is licensed under CC BY 4.0

Please visit the web version of Enhanced Introductory College Chemistry to access the complete book, interactive activities and ancillary resources.

In this chapter, you will learn about

  • Dalton’s atomic theory
  • Basic concepts in electric charge
  • The discoveries of an atom’s subatomic particles atom including electrons, protons, and neutrons
  • The structure of the nuclear atom and how neutral atoms form ions
  • Isotopes of elements and how to read and write isotope symbols
  • Atomic masses of elements and their isotopes and how to calculate percent abundance.

To better support your learning, you should be familiar with the following concepts before starting this chapter:

  • How to reference element names, symbols, and masses from the periodic table
  • How to use your scientific calculator to perform percent calculations
A person is shown blowing into a tube connected to a plastic bag. There is a computer screen displaying data that reads “Mass Spectral Breath Analysis.” An arrow from the plastic bag points to an illustration of different molecular compounds contained in the person’s exhalation
Figure 5a Mass Spectral Breath Analysis: Analysis of molecules in an exhaled breath can provide valuable information, leading to early diagnosis of diseases or detection of environmental exposure to harmful substances. (credit: modification of work by Paul Flowers in Chemistry (OpenStax), CC BY 4.0).

Your overall health and susceptibility to disease depends upon the complex interaction between your genetic makeup and environmental exposure, with the outcome difficult to predict. Early detection of biomarkers, substances that indicate an organism’s disease or physiological state, could allow diagnosis and treatment before a condition becomes serious or irreversible. Recent studies have shown that your exhaled breath can contain molecules that may be biomarkers for recent exposure to environmental contaminants or for pathological conditions ranging from asthma to lung cancer. Scientists are working to develop biomarker “fingerprints” that could be used to diagnose a specific disease based on the amounts and identities of certain molecules in a patient’s exhaled breath. An essential concept underlying this goal is that of a molecule’s identity, which is determined by the numbers and types of atoms it contains, and how they are bonded together. This chapter will describe some of the fundamental chemical principles related to the composition of matter, including those central to the concept of molecular identity.

Attribution & References

Except where otherwise noted, this page is adapted by Jackie MacDonald from “Chapter 2 Introduction” In General Chemistry 1 & 2 by Rice University, a derivative of Chemistry (Open Stax) by Paul Flowers, Klaus Theopold, Richard Langley & William R. Robinson and is licensed under CC BY 4.0. ​Access for free at Chemistry (OpenStax)


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Enhanced Introductory College Chemistry Copyright © 2023 by Gregory Anderson; Caryn Fahey; Jackie MacDonald; Adrienne Richards; Samantha Sullivan Sauer; J.R. van Haarlem; and David Wegman is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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