Test 1 Study Guide: GOB Chemistry

Overview

This study guide covers foundational topics in General, Organic, and Biological (GOB) Chemistry, including matter and energy, the periodic table, atomic structure, and electron energy. The guide is structured to help students prepare for a test consisting of multiple choice, true/false, diagram, matching, and short answer questions. Note: No periodic table will be provided during the test.

Matter and Energy

Classification of Matter

• Pure Substances: Materials with a fixed composition; includes elements and compounds.

• Mixtures: Physical combinations of two or more substances. Can be:

  • Homogeneous mixtures (solutions): Uniform composition throughout (e.g., salt water).

  • Heterogeneous mixtures: Non-uniform composition (e.g., salad, sand in water).

States of Matter

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

• Liquids: Definite volume, indefinite shape; particles are less tightly packed than solids.

• Gases: Indefinite shape and volume; particles are far apart and move freely.

Physical vs. Chemical Changes

• Physical Change: Alters the form or appearance, not the composition (e.g., melting, boiling).

• Chemical Change: Produces new substances with different properties (e.g., rusting, burning).

Changes of State

• Freezing: Liquid to solid

• Melting: Solid to liquid

• Boiling (Vaporization): Liquid to gas

• Condensation: Gas to liquid

• Sublimation: Solid to gas

• Deposition: Gas to solid

Energy and Heat

• Specific Heat: The amount of heat required to raise the temperature of 1 gram of a substance by 1°C.

• Formula:

• Where q = heat (J), m = mass (g), c = specific heat (J/g°C), ΔT = change in temperature (°C).

• Boiling Point: The temperature at which a liquid changes to a gas.

• Heating/Cooling Curve: Graph showing temperature change as heat is added or removed.

Elements and the Periodic Table

Element Names and Symbols

• Be able to correctly spell and identify the chemical symbols for common elements.

Periodic Table Organization

• Periods: Horizontal rows on the periodic table.

• Groups: Vertical columns; elements in the same group have similar chemical properties.

• Metals, Nonmetals, Metalloids:

  • Metals: Shiny, good conductors, malleable.

  • Nonmetals: Dull, poor conductors, brittle.

  • Metalloids: Properties intermediate between metals and nonmetals.

Periodic Trends

• Atomic Size: Increases down a group, decreases across a period.

• Ionization Energy: Energy required to remove an electron; increases across a period, decreases down a group.

• Metallic Character: Increases down a group, decreases across a period.

Atoms and Atomic Structure

Atomic Theory

• All matter is composed of atoms, which are the smallest units of elements.

• Atoms of each element are unique and retain the properties of that element.

Subatomic Particles

• Proton: Positively charged particle in the nucleus.

• Neutron: Neutral particle in the nucleus.

• Electron: Negatively charged particle in orbitals around the nucleus.

Atomic Number, Mass Number, and Isotopes

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

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

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

• Calculating Atomic Mass:

Electron Configuration

• Electrons are arranged in shells, subshells, and orbitals.

• Shells: Main energy levels (n = 1, 2, 3, ...).

• Subshells: s, p, d, f (types of orbitals within shells).

• Electron configuration describes the distribution of electrons among the orbitals.

Lab: Elements

• Be familiar with the properties and identification of common elements.

• Practice writing names and symbols for elements.

Summary Table: Key Concepts

Example: The element sodium (Na) has atomic number 11, meaning it has 11 protons. Its most common isotope has a mass number of 23 (11 protons + 12 neutrons).

Additional info: For exam preparation, practice identifying elements by their symbols, writing electron configurations, and applying periodic trends to predict properties.