Mississippi Science CHE.2

CHE.2 is a cluster heading. These are the individual standards under it.

• CHE.2.1

  Investigate the historical progression leading to the modern atomic theory, including, but not limited to, work done by Dalton, Rutherford’s gold foil experimen...

• CHE.2.2

  Construct models (e.g., ball and stick, online simulations, mathematical computations) of atomic nuclei to explain the abundance weighted average (relative mass...

• CHE.2.3

  Investigate absorption and emission spectra to interpret explanations of electrons at discrete energy levels using tools such as online simulations, spectromete...

• CHE.2.4

  Research appropriate sources to evaluate the way absorption and emission spectra are used to study astronomy and the formation of the universe.

01

What Students Need to Do

Students connect key atomic experiments to the models that followed. They build isotope models and calculate average atomic mass from isotope masses and abundances. They use absorption and emission spectra to explain electron energy changes and identify elements in stars.

02

What Mastery Looks Like

Given an experiment, students can say what its results revealed about the atom. They can calculate a weighted average atomic mass and compare it with a periodic table value. They can match bright lab lines to dark lines in a star’s spectrum and explain why the wavelengths match.

03

Common Misconceptions

Students may still picture atoms as solid balls, despite evidence for electrons and a small nucleus. They often average isotope masses without accounting for abundance. They may think an element’s absorption and emission lines occur at unrelated wavelengths.

04

How to Assess It

Exit ticket: An element has isotopes of 10 amu (20%) and 11 amu (80%). Calculate its average mass, name the experiment that revealed the nucleus, and explain why a dark line in a star’s spectrum could match one of its bright lab lines.

1. 01

   Have pairs build chlorine-35 and chlorine-37 nuclei with two colors of counters, then calculate average mass using 75% and 25% cards.

2. 02

   Ask: What did Rutherford’s gold foil results show that Thomson’s model could not explain? Have students sketch both models beside their answers.

3. 03

   Hand out cards naming Dalton, Thomson, Rutherford, Millikan, and Bohr; teams match each scientist to an experiment, observation, or atomic claim.

4. 04

   Project solar absorption and hydrogen emission spectra; students circle matching wavelengths and explain how astronomers identify hydrogen in the Sun.

• PHS.2

  Students will demonstrate an understanding of both modern and historical theories of atomic structure.

• PHY.6

  Students will demonstrate an understanding of the basic principles of nuclear energy.

• PHS.2.1

  Research and develop models (e.g., 3-D models, online simulations, or ball and stick) to investigate both modern and historical theories of atomic structure. Co...