Question 1
| Element | Atomic radius (picometers) |
|---|---|
| Sodium | 186 |
| Magnesium | 160 |
| Aluminum | 143 |
| Silicon | 118 |
| Phosphorus | 110 |
| Sulfur | 103 |
| Chlorine | 99 |
The table gives the radii of atoms of Period 3 elements. Which explanation accounts for the pattern?
Regents Physical Science: Chemistry: the course and the exam
One three-hour test of 45 to 55 one-credit questions, grouped into 9 to 11 clusters that each follow a phenomenon. Six topics, each with a set share of the test.
26 weeks, 104 hours in all
Start with Topic 2
Chemical Reactions: 36 of your hours. It is 9 of the 24 questions on our timed checks, 38%.
| Topic | Your hours | Share of the checks |
|---|---|---|
| Topic 2: Chemical Reactions | 36 | 38% |
| Topic 1: Structures and Properties of Matter | 32 | 33% |
| Topic 3: Energy | 12 | 13% |
| Topic 6: Engineering, Technology, and the Applications of Science | 8 | 8% |
| Topic 4: Waves and Electromagnetic Radiation | 4 | 4% |
| Topic 5: Matter and Energy in Organisms and Ecosystems | 4 | 4% |
Week by week
- Week 1Topic 2: Chemical Reactions
- Week 2Topic 2: Chemical Reactions
- Week 3Topic 2: Chemical Reactions
- Week 4Topic 2: Chemical Reactions
- Week 5Topic 2: Chemical Reactions
- Week 6Topic 2: Chemical Reactions
- Week 7Topic 2: Chemical Reactions
- Week 8Topic 2: Chemical Reactions
- Week 9Topic 2: Chemical Reactions
- Week 10Topic 1: Structures and Properties of Matter
- Week 11Topic 1: Structures and Properties of Matter
- Week 12Topic 1: Structures and Properties of Matter
- Week 13Topic 1: Structures and Properties of Matter
- Week 14Topic 1: Structures and Properties of Matter
- Week 15Topic 1: Structures and Properties of Matter
- Week 16Topic 1: Structures and Properties of Matter
- Week 17Topic 1: Structures and Properties of Matter
- Week 18Topic 3: Energy
- Week 19Topic 3: Energy
- Week 20Topic 3: Energy
- Week 21Topic 6: Engineering, Technology, and the Applications of Science
- Week 22Topic 6: Engineering, Technology, and the Applications of Science
- Week 23Topic 4: Waves and Electromagnetic Radiation
- Week 24Topic 5: Matter and Energy in Organisms and Ecosystems
- Week 25A timed check and a set of question clusters, then review every lost credit
- Week 26A timed check and a set of question clusters, then review every lost credit
| The test | One written test, three hours |
|---|---|
| Questions | 45 to 55, in 9 to 11 clusters |
| Question types | About 60% multiple choice, 40% constructed response, 1 credit each |
| Tools | A scientific calculator and the 2025 Reference Tables |
The six topics and their share of the test
- Structures and Properties of Matter: 30 to 40%.
- Chemical Reactions: 36 to 46%.
- Energy: 10 to 14%.
Question clusters
Every question sits in a cluster built around one phenomenon. A cluster opens with an introduction that says how many questions it has, then gives several stimuli: reading passages, data tables, graphs, diagrams or photos. Its questions mix multiple choice and constructed response, and each answer adds to an explanation, a model or a design.
Calculator and reference tables
Every student has a scientific calculator for the whole exam, and graphing calculators are allowed once their memory is cleared. Each student also gets a clean copy of the Reference Tables for Physical Science: Chemistry (2025 Edition), with the data and equations you are expected to find and use rather than memorize.
Try 2 questions
Question 2
| Container | Mass before (g) | Mass after (g) |
|---|---|---|
| Open beaker | 152.0 | 151.1 |
| Capped bottle | 71.5 | 71.5 |
Two groups each react 2.0 g of baking soda with 50.0 g of vinegar. Group 1 uses an open beaker; Group 2 uses a small plastic bottle with its cap screwed on. Each group weighs its container and contents before and after (table). Which conclusion is best supported?
Next step
Questions people ask
How many credits is each question worth?
One. Multiple-choice and constructed-response questions are each worth 1 credit.
Can I use a calculator?
Yes: every student must have a scientific calculator, and graphing calculators are allowed with their memory cleared.
What standards does the exam test?
The New York State P-12 Science Learning Standards. Every question draws on science and engineering practices, core ideas and crosscutting concepts together.