What TEAS Chemistry Actually Tests
ATI lists chemistry as one of three Science content areas alongside human anatomy and physiology and biology. In practice, chemistry questions appear in 8-12 items on the Science section, with the following six topic areas covering nearly all of them:
- Atomic structure
- The periodic table and its organization
- Chemical bonding
- Chemical reactions and balancing equations
- Acids and bases
- Solutions and concentration
Each of these is a self-contained topic. You can study them in any order, though the sequence above builds knowledge naturally — atomic structure feeds into bonding, bonding feeds into reactions, reactions feed into acids/bases.
Topic 1: Atomic Structure
The foundation. Master this and the rest of TEAS chemistry follows.
- Subatomic particles: Protons (positive, in nucleus), neutrons (neutral, in nucleus), electrons (negative, in electron cloud).
- Atomic number: Number of protons. Determines what element an atom is.
- Mass number: Protons + neutrons. Listed as a superscript before element symbol.
- Isotopes: Atoms of the same element with different numbers of neutrons. Same chemical properties, different masses.
- Ions: Atoms that have gained or lost electrons. Cations (positive) lost electrons; anions (negative) gained them.
- Electron configuration basics: Electrons fill shells from inside out (2, 8, 18). Outermost shell is the valence shell.
- Valence electrons: Electrons in the outermost shell. Determine bonding behavior.
Common question pattern: "An atom has 11 protons, 12 neutrons, and 11 electrons. What is the mass number?" (Answer: 23. Mass number = protons + neutrons.)
Topic 2: The Periodic Table
Tests how elements are organized — not memorization of every element.
- Periods: Horizontal rows. As you move across, atomic number increases.
- Groups: Vertical columns. Elements in the same group have similar chemical properties.
- Group 1 (Alkali metals): Highly reactive, +1 ion. Includes Li, Na, K.
- Group 2 (Alkaline earth metals): Reactive, +2 ion. Includes Mg, Ca.
- Group 17 (Halogens): Highly reactive nonmetals, -1 ion. Includes F, Cl, Br, I.
- Group 18 (Noble gases): Inert (do not react). Includes He, Ne, Ar.
- Metals vs. nonmetals: Metals on left, nonmetals on right (separated by a stair-step line).
- Atomic radius trend: Decreases across a period, increases down a group.
- Electronegativity trend: Increases across a period, decreases down a group. Fluorine is the most electronegative.
Elements you should recognize by symbol: H, He, Li, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Fe, Cu, Zn.
Topic 3: Chemical Bonding
Two main types tested:
- Ionic bonds: Electrons transferred from metal to nonmetal. One atom becomes positive, the other negative; opposite charges attract. Example: NaCl (sodium gives an electron to chlorine).
- Covalent bonds: Electrons shared between two nonmetals. Example: H2O (oxygen shares electrons with two hydrogens).
- Polar covalent vs. nonpolar covalent: Polar = unequal sharing (water). Nonpolar = equal sharing (O2, N2, methane).
- Hydrogen bonds: Weak attraction between hydrogen and electronegative atoms (O, N, F) on different molecules. Holds water molecules together. Important in biology.
Topic 4: Chemical Reactions and Balancing Equations
Four basic reaction types appear on the TEAS:
- Synthesis: A + B → AB. Two reactants combine into one product.
- Decomposition: AB → A + B. One reactant breaks into multiple products.
- Single replacement: A + BC → AC + B. One element replaces another.
- Double replacement: AB + CD → AD + CB. Two compounds exchange ions.
Balancing equations: Mass is conserved. The number of atoms of each element must be equal on both sides. Adjust coefficients (numbers in front of compounds), never subscripts (numbers within compounds).
Example: H2 + O2 → H2O is unbalanced. Balanced: 2H2 + O2 → 2H2O.
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Try free TEAS practice test →Topic 5: Acids and Bases
- Acids: Donate H+ ions. Taste sour. Turn litmus red. pH below 7.
- Bases: Accept H+ ions (or donate OH-). Taste bitter, feel slippery. Turn litmus blue. pH above 7.
- pH scale: 0-14. 7 is neutral (water). Below 7 is acidic; above 7 is basic. Each whole number is 10x stronger.
- Strong acids: HCl, H2SO4, HNO3. Fully dissociate in water.
- Strong bases: NaOH, KOH. Fully dissociate.
- Buffers: Solutions that resist pH change. Important in biology (blood pH stays around 7.4 due to bicarbonate buffering).
- Neutralization: Acid + base → salt + water. Example: HCl + NaOH → NaCl + H2O.
Topic 6: Solutions and Concentration
- Solute and solvent: Solute is what dissolves; solvent is what does the dissolving. Water is the universal solvent.
- Solubility: Polar substances dissolve in polar solvents (sugar in water). Nonpolar in nonpolar (oil in oil). "Like dissolves like."
- Concentration: Amount of solute per volume of solvent. Common units: molarity (mol/L), percent (g/100mL), parts per million.
- Dilution: Adding solvent to decrease concentration. M1V1 = M2V2.
- Saturation: Maximum amount of solute that can dissolve. Beyond saturation, solute precipitates out.
The 2-Week TEAS Chemistry Study Plan
Chemistry can be covered in 2 weeks of focused study for most students.
- Week 1, Days 1-3: Atomic structure and the periodic table.
- Week 1, Days 4-7: Chemical bonding and reactions (including balancing equations).
- Week 2, Days 1-3: Acids, bases, and pH.
- Week 2, Days 4-5: Solutions and concentration.
- Week 2, Days 6-7: Practice questions across all topics, review weak areas.
Common TEAS Chemistry Mistakes
- Memorizing without understanding. Knowing that NaCl is ionic is a fact. Knowing why (Na is a metal in Group 1, Cl is a nonmetal in Group 17) lets you predict bonding for new compounds you have never seen.
- Skipping balancing practice. Equation balancing is the only TEAS chemistry topic that requires hands-on practice. Reading about it does not build the skill.
- Forgetting pH is logarithmic. A pH of 4 is not "twice as acidic" as pH 5 — it is 10 times more acidic.
- Confusing molarity with molality. The TEAS tests molarity (M, mol/L). Molality is a similar-sounding term tested only in advanced chemistry.
- Overpreparing for organic chemistry. The TEAS does not test organic chemistry beyond simple recognition of carbon compounds. Skip detailed organic reaction mechanisms.
Frequently Asked Questions
How much chemistry is on the TEAS 7?
Chemistry is one of three Science content areas on the TEAS 7 (along with anatomy and physiology and biology). It typically accounts for approximately 8-12 of the 50 Science questions — roughly 20-25% of the Science section.
What chemistry topics are tested on the TEAS?
The TEAS tests basic chemistry: atomic structure, the periodic table, chemical bonding (ionic and covalent), chemical reactions and balancing equations, acids and bases (pH scale), and solutions (concentration, dilution). The level is comparable to high school general chemistry — no organic chemistry, no advanced thermodynamics.
Is the TEAS chemistry section hard?
Most students find TEAS chemistry less difficult than A&P because the content is more rule-based. If you have taken high school chemistry, the topics will be familiar. If chemistry is your weakest area, allocate 1-2 weeks of dedicated study and you should be able to score competitively.
Do I need to memorize the periodic table for the TEAS?
You do not need to memorize the periodic table from memory. You should understand how it is organized (groups, periods, metals vs. nonmetals, valence electron patterns), be able to identify common elements by symbol (H, He, C, N, O, Na, Mg, Cl, K, Ca, Fe), and understand trends like atomic radius and electronegativity. Memorizing every element is unnecessary.
What chemistry topic should I study first for the TEAS?
Atomic structure first — protons, neutrons, electrons, atomic number, mass number, isotopes, ions. Almost every other chemistry topic builds on this. Then move to the periodic table organization, then chemical bonding (ionic vs. covalent), then reactions, then acids/bases, then solutions.
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