Key Takeaways
- Chemistry covers approximately 5 items (~8%) of the NEX Science section — the smallest science subsection
- An atom consists of protons (positive, in nucleus), neutrons (neutral, in nucleus), and electrons (negative, orbiting)
- The atomic number = number of protons; mass number = protons + neutrons
- Elements in the same group (column) of the periodic table share similar chemical properties
- Ionic bonds form when electrons are transferred (metal + nonmetal); covalent bonds form when electrons are shared (nonmetal + nonmetal)
- pH scale: 0-6 is acidic, 7 is neutral, 8-14 is basic (alkaline); blood pH is 7.35-7.45
- The four types of macromolecules: carbohydrates (energy), lipids (insulation/storage), proteins (structure/function), nucleic acids (genetic information)
- Water is essential for life: it is a universal solvent, has high specific heat, and participates in many biochemical reactions
Chemistry Basics
Chemistry covers approximately 5 items (~8%) of the NEX Science section. While it is the smallest science subsection, these concepts are foundational for pharmacology and understanding how medications work in the body.
Atomic Structure
An atom is the smallest unit of an element that retains the properties of that element.
| Subatomic Particle | Charge | Location | Mass |
|---|---|---|---|
| Proton | Positive (+) | Nucleus | 1 amu |
| Neutron | Neutral (0) | Nucleus | 1 amu |
| Electron | Negative (-) | Electron cloud (orbiting) | ~0 amu |
Key numbers:
- Atomic number = number of protons (determines the element)
- Mass number = protons + neutrons
- Neutral atom: # protons = # electrons
- Ion: Atom with a charge due to gaining or losing electrons
The Periodic Table
The periodic table organizes elements by atomic number and chemical properties:
| Feature | Description |
|---|---|
| Periods | Horizontal rows (1-7); elements get heavier left to right |
| Groups | Vertical columns (1-18); elements share similar properties |
| Metals | Left side; conduct heat/electricity, malleable, shiny |
| Nonmetals | Right side; poor conductors, brittle as solids |
| Metalloids | Along the staircase line; properties of both metals and nonmetals |
Important groups:
- Group 1: Alkali metals (highly reactive: Li, Na, K)
- Group 17: Halogens (reactive nonmetals: F, Cl, Br, I)
- Group 18: Noble gases (unreactive: He, Ne, Ar)
Chemical Bonding
| Bond Type | How It Forms | Strength | Example |
|---|---|---|---|
| Ionic | Electrons transferred (metal + nonmetal) | Strong | NaCl (table salt) |
| Covalent | Electrons shared (nonmetal + nonmetal) | Strong | H₂O (water) |
| Hydrogen | Weak attraction between H and N/O/F | Weak | Between water molecules |
Acids, Bases, and pH
The pH scale measures how acidic or basic a solution is:
| pH | Classification | Examples |
|---|---|---|
| 0-6 | Acidic | Stomach acid (1-2), vinegar (3), coffee (5) |
| 7 | Neutral | Pure water |
| 8-14 | Basic (alkaline) | Baking soda (9), bleach (12), drain cleaner (14) |
Critical nursing value: Normal blood pH is 7.35 to 7.45 (slightly basic).
- Below 7.35 = acidosis (dangerous)
- Above 7.45 = alkalosis (dangerous)
Macromolecules
The four major biological macromolecules:
| Macromolecule | Building Block | Function | Examples |
|---|---|---|---|
| Carbohydrates | Monosaccharides (sugars) | Quick energy, structural support | Glucose, starch, cellulose |
| Lipids | Fatty acids + glycerol | Long-term energy, insulation, cell membranes | Fats, oils, cholesterol, phospholipids |
| Proteins | Amino acids | Structure, enzymes, transport, immunity | Hemoglobin, insulin, antibodies |
| Nucleic Acids | Nucleotides | Genetic information storage and transfer | DNA, RNA |
Water and Solutions
Water is essential for life due to its unique properties:
| Property | Significance |
|---|---|
| Universal solvent | Dissolves many substances for transport in the body |
| High specific heat | Resists temperature changes; helps regulate body temperature |
| Cohesion | Water molecules stick together (surface tension) |
| Polarity | Positive and negative ends; enables hydrogen bonding |
Solution terminology:
- Solute: The substance being dissolved (e.g., salt)
- Solvent: The substance doing the dissolving (e.g., water)
- Solution: Homogeneous mixture of solute + solvent (e.g., saline)
What is the normal pH range of human blood?
Which type of chemical bond forms when electrons are TRANSFERRED from one atom to another?
Which macromolecule is the body's PRIMARY source of quick energy?
Match each macromolecule to its building block (monomer).
Match each item on the left with the correct item on the right
The atomic number of an element tells you the number of:
A solution with a pH of 3 is classified as _____.
Type your answer below
Water is considered a "universal solvent" because:
Elements in the same GROUP (column) of the periodic table share similar: