Chemistar: Resources for the Chemistry Student and Science Teacher

**Chemistry Unit 4: Atomic Structure Part 2**
Goals: Describe the experimental evidence for historical models of the atom. Discuss the experimental evidence and explain its influence on the development of	Course Essential Questions How are a system’s characteristics, form, and function attributed to the quantity, type, and nature of its components? How might scientific inquiry be used to investigation the natural world?
Unit Essential Questions What experimental evidence led to the formation of models of the atom? What changes were made to each model as questions were asked? What model of the atom is currently accepted by the scientific community? Why? How are the characteristics of elements attributed to the quantity, type, and nature of atoms?	Understandings Experimental evidence leads to the development of models and/or theories as possible explanations. Scientific models are refined as questions about the model lead to further investigation. The Quantum Mechanical Model is the currently accepted explanation of atomic structure based on many different kinds of empirical evidence. Atomic structure is responsible for the physical and chemical properties of elements.
Students will know.... Terms: Use the atomic number, atomic mass, and mass number to find the number of protons, neutrons, and electrons in a neutral atom of a given element Ions are charged atoms or groups of chemically bonded atoms. Ions form when atoms or group of chemically bonded atoms gain or lose electrons. Electrons in the outer energy level of an atom are known as valence electrons. Conceptual and mathematical relationships betwen energy, light, and electrons	Students will be able to.... Define theory. Explain why the Atomic Theory is a theory. Interpret the experiments of Thomson, Millikan, and Rutherford and explain how their results impacted the formation of an early atomic model. Formulate 2 investigative questions about atomic structure that are not explained by the Plum Pudding Model. Describe Rutherford' work and explain how he used the results to formulate the Solar System Model. Describe the role of Bunsen and Rydberg's work with atomic spectra in the modification of the atomic model. State common misconceptions people may have about the structure of atoms. Formulate an explanation of the quantum model
Links and Resources Elementary Particles - from the University of Oregon Origins of Atomic Lines - comprehensive and understandable description of the ODGs who did the experiments. Light and Energy - yes, this is from Wikipedia. It's good. Electromagnetic Waves - storylike explanation of atomic structure with lots of interactives. I suggest going to this page about the quantum atom, starting with Bohr's model. Electromagnetic Spectrum - a series of 5 minute videos from NASA explaining the electromagnetic spectrum. Wavelength, Frequency, and Energy -interactive. Select areas of the spectrum to see how energy varies with color. Absorption Spectra - Click an element on the periodic table to see its absorption spectrum Rutherford's Gold Foil Experiment, explained (Youtube) Grand Orbital Table -representations of how orbitals would look if we could see them. Electron Configurations - from chemwiki

**Daily Learning Activities**
Day 1	Electromagnetic spectrum; visible light properties.
Day 2	Flame Test Lab prep and data collection.
Day 3	Review Ion Quiz; self-correct. Analysis of Flame Test Lab in terms of Bunsen and Rydberg's atomic spectra work leading to the Bohr Model. Interpretation of gas tube spectral lines. Light, Wavelength and Frequency problems
Day 4	Blackbody Radiation, the Photoelectric Effect, and the dual wave-particle nature of light. Planck's Constant and Energy problems
Day 5	Electrons in Atoms: Electron Configurations
Day 6	Proficiency

Learning Targets:

Describe the structure of the atom.
Explain how the work of Dalton, Thomson, Millikan, Rutherford, Bunsen,Rydburg, Planck, Einstein, Bohr, deBroglie, and Schroedinger contributed evidence to the quantum mechanical model of the atom that is currently accepted by science.

Oregon State Standards:
H.3S.4 Identify examples from the history of science that illustrate modification of scientific knowledge in light of challenges to prevailing explanations.
H.1P.1 Explain how atomic structure is related to the properties of elements and their position in the Periodic Table. Explain how the composition of the nucleus is related to isotopes and radioactivity.

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