Chapter 1: Chemistry Basics - Matter and Measurement

Phases of Matter

The three primary phases of matter are solid, liquid, and gas. Each phase is characterized by the arrangement and movement of particles.

• Solids: Definite shape and volume; particles are closely packed and vibrate in place.

• Liquids: Definite volume but no definite shape; particles are less tightly packed and can flow past one another.

• Gases: No definite shape or volume; particles are far apart and move freely.

Chemical and Physical Changes

Physical changes alter the form or appearance of matter but do not change its composition. Chemical changes result in the formation of new substances with different properties.

• Physical change example: Melting ice to water.

• Chemical change example: Burning wood to form ash and gases.

SI System and Unit Conversions

The SI system (International System of Units) is the standard for scientific measurements. Common units include meter (m), kilogram (kg), and second (s).

• Unit conversions: Use conversion factors to change from one unit to another (e.g., 1 inch = 2.54 cm).

• Temperature scales: Celsius (°C), Kelvin (K), and Fahrenheit (°F).

Temperature conversion formulas:

Dosing

Dosing calculations often require unit conversions, especially in medical and pharmaceutical contexts.

• Example: Converting mg/kg to total mg for a patient's weight.

Accuracy, Precision, and Significant Figures

• Accuracy: How close a measurement is to the true value.

• Precision: How close repeated measurements are to each other.

• Significant figures (sig figs): Digits in a measurement that are known with certainty plus one estimated digit.

Calculations with sig figs: The result should have the same number of significant figures as the measurement with the fewest sig figs.

Scientific Notation

Scientific notation expresses numbers as a product of a coefficient and a power of ten.

• Example:

Chapter 2: Atoms and Radioactivity

Types of Subatomic Particles

• Protons: Positively charged particles in the nucleus.

• Neutrons: Neutral particles in the nucleus.

• Electrons: Negatively charged particles orbiting the nucleus.

Structure of the Atom

An atom consists of a dense nucleus (protons and neutrons) surrounded by electrons in defined energy levels.

Isotopes

Isotopes are atoms of the same element with different numbers of neutrons, resulting in different mass numbers.

• Example: Carbon-12 and Carbon-14 are isotopes of carbon.

Nuclear Symbols

Nuclear symbols represent isotopes and include the element symbol, atomic number, and mass number.

• General form: where X = element symbol, A = mass number, Z = atomic number.

Types of Radioactive Decay

• Alpha decay (α): Emission of an alpha particle ().

• Beta decay (β): Emission of a beta particle (electron or positron).

• Gamma decay (γ): Emission of gamma radiation (high-energy photons).

Decay Equations

Radioactive decay can be represented by nuclear equations showing the transformation of one nucleus into another.

• Example: (beta decay)

Amount Remaining Calculations and Half-Life

The half-life is the time required for half of a radioactive sample to decay.

• Amount remaining formula:

• Where: N = amount remaining, = initial amount, t = elapsed time, = half-life.

Chapter 3: Compounds - How Elements Combine

Electron Shell Filling and the Octet Rule

Electrons fill energy levels (shells) around the nucleus. The octet rule states that atoms tend to gain, lose, or share electrons to achieve eight electrons in their outer shell.

Formation of Ions

• Cations: Positively charged ions formed by loss of electrons.

• Anions: Negatively charged ions formed by gain of electrons.

Ionic Bonding

Ionic bonds form between metals and nonmetals through the transfer of electrons, resulting in oppositely charged ions that attract each other.

• Example: NaCl (sodium chloride) forms from Na+ and Cl-.

Ionic Compounds: Formation and Composition

Ionic compounds are composed of cations and anions in ratios that yield a neutral compound.

• Compounds with transition metals: Transition metals can form ions with different charges; Roman numerals indicate the charge (e.g., Fe(III) = Fe3+).

• Compounds with polyatomic ions: Polyatomic ions are groups of atoms with a net charge (e.g., SO42-).

Covalent Bonding Principle

Covalent bonds form when two nonmetals share electrons to achieve stable electron configurations.

• Example: H2O (water) forms by sharing electrons between hydrogen and oxygen.

Lewis Structures of Covalent Compounds

Lewis structures are diagrams that show the bonding between atoms and the arrangement of valence electrons.

• Steps: Count valence electrons, arrange atoms, form bonds, and distribute remaining electrons as lone pairs.

Naming Covalent Compounds

Covalent compounds are named using prefixes to indicate the number of each type of atom (e.g., CO2 is carbon dioxide).

• Prefixes: mono-, di-, tri-, tetra-, penta-, etc.