Study guide
4.8 Chemistry Basics
ATI TEAS 7 Nursing Admission
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1 Introduction to the ATI TEAS 7
1.1 About the ATI TEAS 7 Exam 1.2 Content Area Breakdown 1.3 Scoring and Program Requirements 1.4 Building Your TEAS Study Plan
2 Reading
2.1 Identifying the Main Idea 2.2 Making Inferences and Drawing Conclusions 2.3 Summarizing and Paraphrasing 2.4 Understanding Text Structure 2.5 Author's Purpose, Tone, and Point of View 2.6 Evaluating Arguments, Evidence, and Credibility 2.7 Integrating Information and Interpreting Graphics 2.8 TEAS Reading Strategies, Pacing, and Practice
3 Mathematics
3.1 Whole Numbers and Basic Operations 3.2 Fractions 3.3 Decimals and Percentages 3.4 Ratios and Proportions 3.5 Algebra and Equations 3.6 Measurement and Unit Conversions 3.7 Statistics and Data Interpretation 3.8 Geometry Basics
4 Science
4.1 The Cardiovascular System 4.2 The Respiratory System 4.3 The Digestive System 4.4 The Nervous System 4.5 The Musculoskeletal System 4.6 The Urinary and Reproductive Systems 4.7 Cell Biology and Genetics 4.8 Chemistry Basics 4.9 Scientific Reasoning and the Scientific Method
5 English & Language Usage
5.1 Grammar and the Parts of Speech 5.2 Sentence Structure 5.3 Punctuation 5.4 Spelling and Word Usage 5.5 Vocabulary in Context and Word Parts 5.6 Paragraph Organization and the Writing Process 5.7 Formal vs. Informal Language, Audience, and Tone 5.8 TEAS English Section Strategies and Pacing
4.8 Chemistry Basics
Key Takeaways Explain This Topic AI
Protons (+) and neutrons (0) sit in the nucleus; electrons (-) occupy shells; atomic number = protons, mass number = protons + neutrons
Ionic bonds transfer electrons (metal + nonmetal); covalent bonds share electrons (nonmetal + nonmetal)
The pH scale is logarithmic: each unit is a 10-fold change in H+ concentration; below 7 is acidic, 7 neutral, above 7 basic, blood ~7.4
Reaction types: synthesis, decomposition, single replacement, double replacement, and combustion; mass is conserved when balancing
- Molarity (mol/L) measures concentration; exothermic reactions release energy, endothermic reactions absorb it
- Last updated: June 2026
Why Chemistry Is on a Nursing Exam
The ATI TEAS 7 tests fundamental chemistry because medications, body fluids, and lab values are all chemistry in action. You will need to read atomic structure, predict bond types, recognize reaction patterns, balance simple equations, and interpret the pH scale — the same scale nurses use to read arterial blood gases.
Atomic Structure
- Particle Charge Location Mass
- Proton Positive (+) Nucleus ~1 amu
- Neutron Neutral (0) Nucleus ~1 amu
- Electron Negative (–) Electron shells ~0 amu
Three numbers define an atom:
Atomic number = number of protons — this identifies the element.
Mass number = protons + neutrons.
Atomic mass = weighted average of an element's isotopes (atoms with different neutron counts).
Reading the Periodic Table
- Group Members Key Property
- Alkali metals Li, Na, K Very reactive, 1 valence electron
- Alkaline earth metals Mg, Ca Reactive, 2 valence electrons
- Halogens F, Cl, Br, I Very reactive nonmetals, 7 valence electrons
- Noble gases He, Ne, Ar Unreactive, full outer shell
Periods are the horizontal rows (each row adds an electron shell).
Groups are the vertical columns (members share chemical properties because they have the same number of valence electrons , the outermost electrons that drive bonding).
Chemical Bonding
- Bond What Happens Forms Between Example
- Ionic Electrons transfer Metal + nonmetal NaCl (table salt)
- Covalent Electrons shared Nonmetal + nonmetal H2O (water)
- Hydrogen Weak attraction H to O, N, or F Between water molecules
A quick test for any bonding question: transfer = ionic, share = covalent. Atoms bond to reach a full outer shell (the octet rule, eight valence electrons).
The Five Reaction Types
- Type Pattern Example
- Synthesis A + B to AB 2H2 + O2 to 2H2O
- Decomposition AB to A + B 2H2O to 2H2 + O2
- Single replacement A + BC to AC + B Zn + 2HCl to ZnCl2 + H2
- Double replacement AB + CD to AD + CB AgNO3 + NaCl to AgCl + NaNO3
- Combustion Fuel + O2 to CO2 + H2O CH4 + 2O2 to CO2 + 2H2O
- Balancing by Conservation of Mass
The law of conservation of mass says atoms are never created or destroyed in a reaction, so the same number of each atom must appear on both sides. You balance by adjusting coefficients (the big numbers in front), never the subscripts.
Worked Example: Balance H2 + O2 to H2O.
Unbalanced count: left has 2 H and 2 O; right has 2 H and only 1 O.
Place a coefficient of 2 on water: H2 + O2 to 2H2O. Now the right has 4 H and 2 O.
Balance hydrogen by placing 2 in front of H2: 2H2 + O2 to 2H2O.
Final check: 4 H and 2 O on each side. Balanced.
States of Matter
- State Shape Volume Particle Motion
- Solid Fixed Fixed Vibrate in place
- Liquid Takes container Fixed Slide past each other
- Gas Takes container Expands to fill Move fast and freely
Adding energy drives changes of state: melting (solid to liquid), vaporization (liquid to gas); removing energy drives freezing and condensation .
Acids, Bases, and the pH Scale
- Property Acids Bases
- pH Below 7 Above 7
- H+ ions Donate H+ Accept H+
- Taste / feel Sour Bitter, slippery
- Examples HCl, vinegar, citrus NaOH, ammonia, soap
The pH scale runs 0–14 and is logarithmic : each one-unit change equals a ten-fold change in hydrogen-ion concentration. So pH 3 has ten times more H+ than pH 4 and is ten times more acidic. Pure water is neutral at 7 , and human blood is tightly held near 7.4 .
Solutions and Concentration
A solution is a solute dissolved in a solvent (water is the universal solvent). Concentration is most often given as molarity (M) — moles of solute per liter of solution . Diluting a solution with more solvent lowers its molarity. Reactions that release energy are exothermic (give off heat); those that absorb energy are endothermic .
pH Worked Example: A solution measures pH 5; a second measures pH 2. How much more acidic is the second? Each pH unit is one factor of ten, and the gap is 5 − 2 = 3 units, so the pH 2 solution is 10 x 10 x 10 = 1,000 times more acidic than the pH 5 solution.