Wyoming Science HS-PS1-2

ScienceGrades 9–12Physical Science

The Standard

Construct an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties, and revise, as needed.

2023 Wyoming Science Content and Performance Standards · PS1 Matter and Its Interactions

Teacher's field guide

What This Standard Means

What Students Need to Do: Students use periodic table groups to work out how many outer electrons atoms have. They use those electrons to explain what forms in a reaction and revise a prediction when it does not fit.
What Mastery Looks Like: Given magnesium and chlorine, a student predicts MgCl₂ and shows one electron moving from magnesium to each chlorine atom. They can use that model to correct an earlier prediction of MgCl.
Common Misconceptions: Students may write MgCl because there are two kinds of atoms, missing the need for two chlorine atoms. Some draw electrons appearing or disappearing instead of moving between atoms.
How to Assess It: Exit ticket: A student predicts MgCl when magnesium reacts with chlorine. Explain why MgCl₂ forms instead, using outer electrons and periodic table groups.

Lesson moves

Ways to Teach It

Give pairs one magnesium card, two chlorine cards, and counters; have them transfer outer electrons and build MgCl₂.
Ask partners: Why does magnesium form MgO with oxygen, but neon rarely reacts? Point to each atom’s outer electrons.
Deal Na, Mg, Cl, and O cards; partners race to match a metal and nonmetal, then write a charge-balanced formula.
Show a table salt label and a sodium metal safety warning; ask why sodium chloride behaves differently from sodium.

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