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Why This Matters for Nursing: Chemistry is the foundation of pharmacology, lab values, and body chemistry. Understanding atoms and molecules helps you understand medications, electrolytes, and diagnostic tests.
Chemistry is the study of matter and how it changes. All matter is made of atoms.
Atom Structure: "PEN" - Protons = Positive (in nucleus) - Electrons = around the outside, nEgative - Neutrons = Neutral (in nucleus)
Elements in the Body: "CHNOPS" Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur
| Particle | Charge | Location | Mass |
|---|---|---|---|
| Proton | Positive (+) | Nucleus | 1 amu |
| Neutron | Neutral (0) | Nucleus | 1 amu |
| Electron | Negative (-) | Orbits/shells | ~0 amu |
| Term | Definition | Example |
|---|---|---|
| Element | Pure substance; one type of atom | Oxygen (O), Carbon (C) |
| Compound | Two or more elements chemically bonded | Water (H₂O), Salt (NaCl) |
| Molecule | Two or more atoms bonded together | O₂, H₂O |
| Mixture | Combined but not chemically bonded | Air, blood |
| Element | Symbol | Role |
|---|---|---|
| Oxygen | O | Cellular respiration |
| Carbon | C | Backbone of organic molecules |
| Hydrogen | H | Part of water and organic molecules |
| Nitrogen | N | Proteins, DNA |
| Calcium | Ca | Bones, muscle contraction, blood clotting |
| Potassium | K | Nerve function, muscle contraction |
| Sodium | Na | Nerve function, fluid balance |
| Iron | Fe | Hemoglobin (oxygen transport) |
| Bond Type | Description | Strength | Example |
|---|---|---|---|
| Ionic | Transfer of electrons | Strong | NaCl (salt) |
| Covalent | Sharing of electrons | Strong | H₂O, O₂ |
| Hydrogen | Attraction to H in another molecule | Weak | Water molecules |
Ion = Atom that gained or lost electrons
| Ion Type | Charge | How Formed | Example |
|---|---|---|---|
| Cation | Positive (+) | Lost electrons | Na⁺, K⁺, Ca²⁺ |
| Anion | Negative (-) | Gained electrons | Cl⁻, HCO₃⁻ |
Electrolytes are ions that conduct electricity in solution: - Sodium (Na⁺) — Fluid balance - Potassium (K⁺) — Heart function - Calcium (Ca²⁺) — Muscles, bones - Chloride (Cl⁻) — Fluid balance
Question: An atom has 6 protons. What element is it?
Step 1 — Know what the atomic number tells you. Every element is defined by its number of protons — this is called the atomic number. No two elements have the same number of protons. It's like a fingerprint. The periodic table lists elements in order of atomic number.
Step 2 — Apply the rule. The question says "6 protons." Atomic number 6 = Carbon (C). You don't need to memorize the whole periodic table — but carbon (6), hydrogen (1), oxygen (8), and nitrogen (7) are the most important elements for biology, and knowing them is enough for the TEAS.
Step 3 — Why carbon matters. Carbon is the backbone of ALL organic (living) molecules — carbohydrates, proteins, lipids, nucleic acids are all built on carbon chains. It's the foundation of life chemistry.
Answer: Carbon — 6 protons = atomic number 6 = Carbon.
The worked examples and practice problems are the part that actually prepares you for the TEAS.
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