Chemistry Outcomes Review: Chapter 3

Origin of Atoms

In this chapter we have discussed the nuclear processes in stars that are responsible for the formation of the elements we find in the present-day universe. We reviewed the structure of atoms and introduced spectroscopy as a method for learning about the identity and relative amounts of atoms in samples that emit light.

After practice in balancing nuclear reactions, we showed how the mass-to-energy conversion in nuclear reactions explains their enormous energy release. Nuclear binding energies determine whether a nucleus will undergo fusion or fission reactions and help explain the cosmic abundance of the elements. The elements formed in the first stars (and still being formed in present stars) are the matter from which planets, including the Earth, are formed and from which life can evolve.

Check your understanding of the ideas in the chapter by reviewing these expected outcomes of your study.

You should be able to:

  • Write the complete symbol and locate the subatomic particles in a diagram of any isotope of an elemental atom or ion [Section 3.1].
  • Describe a spectrograph and how it produces the spectrum from its light source [Section 3.2].
  • Distinguish between continuous and line spectra, identify an element from its line emission spectrum, and determine relative amounts of two elements by the brightness of their emission lines [Sections 3.2 and 3.6].
  • Explain cosmic condensation and nuclear fusion events as a function of the temperatures that make them possible [Section 3.3].
  • Write and balance reactions along the pathway for the formation of elements up to about 56Fe in the first stars [Sections 3.3 and 3.4].
  • Write and balance reactions along the pathway for the formation of elements beyond 56Fe in the first stars [Sections 3.3 and 3.4].
  • Describe the formation of planetary systems and the source of their elementary atoms [Sections 3.3 and 3.7].
  • Balance nuclear reactions (fusion, fission, and radioactive decay) by supplying the appropriate reactant or product nuclei and/or other particles [Section 3.4].
  • Use half lives to find the amount of a radioactive nucleus remaining after an elapsed time or to find the time elapsed since decay began [Sections 3.4 and 3.7].
  • Determine the energy released by mass-to-energy conversion in nuclear fusion and fission reactions [Section 3.5].
  • Determine nuclear binding energies from mass-to-energy conversion in formation of nuclei from protons and neutrons [Section 3.5].
  • Use nuclear binding energies to predict whether a nucleus is likely to undergo fusion or fission [Section 3.5].
  • Give the requirements for a nuclear chain reaction and diagram the differences between controlled and uncontrolled chain reactions [Section 3.5].
  • Use abundance data to estimate abundances of elements relative to one another in the universe, on Earth, and in organisms [Section 3.6].
  • Use nuclear binding energies to explain trends in cosmic elemental abundances as well as deviations from the trends [Section 3.6].
  • Use the model for planetary formation to explain the structure of the Earth [Section 3.7].
  • Use the model for planetary formation to explain the abundance of elements in the Earth's crust [Section 3.7].
  • Relate cosmic elemental abundances to possible evolution of carbon-based life [Section 3.7].