General Chemistry: Foundations and Atomic Structure (Chapters 1-2 Study Guide)

Chapters 1-2: Study Guide Overview

Chapter 1: Introduction to Chemistry

This chapter introduces the fundamental concepts and language of chemistry, including the scientific method, measurement, and the classification of matter.

• Definitions of Boldfaced Words and Major Terms: Understanding key vocabulary is essential for mastering chemistry concepts.

• Chemistry as the Central Science: Chemistry connects physical sciences with life and applied sciences, serving as a bridge between disciplines.

• The Scientific Method: A systematic approach to research involving observation, hypothesis formation, experimentation, and theory development.

• Scientific Notation and Mathematical Functions: Numbers are often expressed in scientific notation (e.g., $3.2 \times 10^4$) for clarity and convenience. Mathematical functions include addition, subtraction, multiplication, and division.

• Significant Figures: The digits in a measurement that are known with certainty plus one estimated digit. Rules determine how many significant figures to report in calculations.

• SI Measurement System: The International System of Units (SI) is the standard for scientific measurements. There are 4 SI base units commonly used: meter (length), kilogram (mass), second (time), and mole (amount of substance).

• Metric Prefixes: Prefixes such as kilo-, centi-, and milli- denote powers of ten. For example, 1 kilometer (km) = $1 \times 10^3$ meters.

• Unit Conversion (Dimensional Analysis): A method for converting between units using conversion factors. For example, to convert inches to centimeters: $1 \text{ in} = 2.54 \text{ cm}$.

• Temperature Scales: Common scales include Celsius (°C), Fahrenheit (°F), and Kelvin (K). Conversion formulas:

  • $K = ^\circ C + 273.15$

  • $^\circ F = (9/5)\times ^\circ C + 32$

• Density Calculations: Density is mass per unit volume: $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$.

• Physical vs. Chemical Changes/Properties:

  • Physical Change: Alters form but not composition (e.g., melting ice).

  • Chemical Change: Alters composition, forming new substances (e.g., rusting iron).

• Classification of Matter: Matter can be classified as pure substances (elements and compounds) or mixtures (homogeneous and heterogeneous).

• Separation Techniques: Methods such as distillation and filtration are used to separate mixtures based on physical properties.

Chapter 2: Atomic Structure and the Periodic Table

This chapter explores the historical development of atomic theory, the structure of the atom, and the organization of elements in the periodic table.

• Early Atomic Theories: Ancient Greek and Chinese philosophers proposed early models of matter, but lacked experimental evidence.

• Dalton's Atomic Theory: John Dalton proposed that matter is composed of indivisible atoms, each element has identical atoms, and chemical reactions involve rearrangement of atoms.

• Discovery of Subatomic Particles:

  • Electron: Discovered by J.J. Thomson using cathode ray experiments.

  • Proton: Discovered by Ernest Rutherford through gold foil experiments.

  • Neutron: Discovered by James Chadwick.

• Atomic Number, Mass Number, and Isotopes:

  • Atomic Number (Z): Number of protons in the nucleus.

  • Mass Number (A): Total number of protons and neutrons.

  • Isotopes: Atoms of the same element with different numbers of neutrons.

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

• Periodic Table: Elements are arranged by increasing atomic number. Groups (columns) share similar properties.

• Metals, Nonmetals, and Metalloids:

  • Metals: Good conductors, malleable, ductile.

  • Nonmetals: Poor conductors, brittle.

  • Metalloids: Properties intermediate between metals and nonmetals.

• Monatomic and Diatomic Elements: Some elements exist as single atoms (monatomic), while others (e.g., O2, N2) are diatomic in nature.

• Periodic Table Organization: The periodic table is organized by atomic number, with elements in the same group having similar chemical properties.

• Electrical Conductivity: Metals conduct electricity due to free-moving electrons; nonmetals generally do not.

• Compound Formation: Atoms combine in specific ratios to form compounds. Chemical formulas represent these ratios (e.g., H2O).

• Testing for Compounds: Chemical tests can identify the presence of certain compounds based on their reactions.

Additional Information

• Know how to convert between English and SI units using conversion factors (e.g., $1 \text{ in} = 2.54 \text{ cm}$).

• Memorize metric prefixes as indicated in class (e.g., kilo-, centi-, milli-).