Mississippi Science PHS.2.1
The Standard
- PHS.2
- Students will demonstrate an understanding of both modern and historical theories of atomic structure.
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. Compare models and contributions of Dalton, Thomson, Rutherford, Bohr, and of modern atomic theory.
2026 Mississippi College- and Career-Readiness Standards for Science · Atomic Theory
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students research and build models of Dalton’s, Thomson’s, Rutherford’s, Bohr’s, and the modern view of the atom. They compare what each model shows and explain why new evidence led to changes.
What Mastery Looks Like
- A student can sketch and label all five models in order. They can explain how gold foil results supported a small nucleus and how the modern electron cloud differs from Bohr’s fixed paths.
Common Misconceptions
- Students often draw a nucleus in Dalton’s or Thomson’s model. They treat Bohr’s electron paths as literal tracks in the modern model. Some mistake an electron cloud for a substance rather than a map of likely locations.
How to Assess It
- Exit ticket: Draw five quick atom sketches in order, labeled Dalton, Thomson, Rutherford, Bohr, and modern. Circle the first model with a nucleus and name the gold foil observation that supports it.
Lesson moves
Ways to Teach It
Give pairs clay, beads, wire, and dotted paper to build five labeled models, from Dalton’s sphere to an electron probability cloud.
Ask: Why did a few alpha particles bounce back in Rutherford’s gold foil experiment, and why would Thomson’s model not predict that?
Play a card sort with five atom sketches and five clue cards; pairs match each sketch to a clue and defend two matches.
Show a neon sign photo and ask students to explain its color using electron energy changes, without drawing fixed electron paths.
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Related Standards
- PHS.2
Students will demonstrate an understanding of both modern and historical theories of atomic structure.
- P.7.5C.1
Develop and use models that explain the structure of an atom.
- 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
Students will demonstrate an understanding of the atomic structure and the historical developments leading to modern atomic theory.
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