HS-PS1-2

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Construct and revise 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.

Clarification statement: Examples of chemical reactions could include the reaction of sodium and chlorine, of carbon and oxygen, or of carbon and hydrogen.

Assessment boundary: Assessment is limited to chemical reactions involving main group elements and combustion reactions.

Regents Exam Questions

Released New York State Regents exam questions that assess HS-PS1-2 are listed here by exam and question cluster. Each link opens the question with its answer key.

Exam	Cluster	Question
August 2026 Chemistry Regents	Semiconductors	Question 16
	Pool Water Chemistry	Question 22
	Safe Transport of Drinking Water	Question 47
June 2026 Chemistry Regents	How Glow Became Gloom	Question 3
	All About Aluminum	Question 43
Chemistry sample clusters (Spring 2025)	Evaluating Gas Stoves	Question 1

Vocabulary

Terms from the Chemistry Glossary that come from this standard or from the released exam questions that assess it.

From this standard

• atom
• chemical property
• chemical reaction
• combustion reaction
• electron state
• element
• evidence
• investigation
• main-group element
• matter
• nucleus
• outermost electron state
• periodic table
• phenomenon
• properties
• proton
• reactant
• reaction
• system
• trend
• trends in the periodic table

From released exam questions

• aqueous (aq) – Aug 2026
• chemical formula – Aug 2026, June 2026, Sample 2025
• claim – Aug 2026
• climate change – Sample 2025
• compound – Aug 2026, June 2026
• concentration – Aug 2026
• electron – Aug 2026, June 2026
• hydrocarbon – Sample 2025
• insoluble – Aug 2026
• ion – Aug 2026, June 2026
• ionization – Aug 2026
• metal – Aug 2026
• outermost energy level – Aug 2026
• oxidation state – Aug 2026
• pH – Aug 2026
• precipitate – Aug 2026
• product – Aug 2026, June 2026, Sample 2025
• semiconductor – Aug 2026
• solution – June 2026
• temperature – Aug 2026

Implied by this standard

• sodium chloride – implied by "the reaction of sodium and chlorine"

Performance Level Descriptions

Every Regents exam question on HS-PS1-2 is written to match one of the performance level descriptions (PLDs) below.

Level 1: Given possible reaction outcomes, identify the outcome of a simple chemical reaction using the outermost electron states of atoms, trends in the periodic table, or knowledge of the patterns of chemical properties. Aug 2026 · Q47 Aug 2026 · Q16 June 2026 · Q3

Level 2: Predict the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and/or knowledge of the patterns of chemical properties. Aug 2026 · Q22 June 2026 · Q43

Level 3: Construct or revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and/or knowledge of the patterns of chemical properties. Sample · Gas Stoves Q1

Level 4: Construct and revise 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.

Level 5: Construct, revise, and evaluate explanations for the outcome of simple chemical reactions based on the predictable behavior of reactants, the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.

Notice: PLD levels!

Resources

Examples and discussion of resources for the learning, teaching, and assessment of HS-PS1-2.

This section could be expanded upon. You can help out by adding to this section.

NGSS Dimensions

Performance expectation HS-PS1-2 was developed using the following elements from the NRC document A Framework for K-12 Science Education:

Science and Engineering Practices

• Constructing Explanations and Computational Thinking
  • Construct and revise an explanation based on valid and reliable evidence obtained from a variety of sources (including students’ own investigations, models, theories, simulations, peer review) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future.

Disciplinary Core Ideas

• PS1.A: Structure and Properties of Matter
  • The periodic table orders elements horizontally by the number of protons in the atom's nucleus and places those with similar chemical properties in columns. The repeating patterns of this table reflect patterns of outer electron states.
• PS1.B: Chemical Reactions
  • The fact that atoms are conserved, together with knowledge of the chemical properties of the elements involved, can be used to describe and predict chemical reactions.

Crosscutting Concepts

• Patterns
  • Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanations of phenomena.

Page contributors: Caroline Leonard, Conrad Richman

Chemistry | HS. Chemical Reactions