Chapter 1: Introduction to Chemistry and the Periodic Table

Elements, Compounds, and Mixtures

This section introduces the fundamental types of matter and their distinguishing characteristics.

• Element: A pure substance consisting of only one type of atom. Example: O2 (oxygen gas).

• Compound: A substance formed when two or more elements are chemically bonded. Example: H2O (water).

• Mixture: A physical combination of two or more substances that retain their individual properties. Example: air (a mixture of gases).

Physical and Chemical Changes

• Physical Change: Alters the form or appearance of matter but does not change its composition (e.g., melting ice).

• Chemical Change: Results in the formation of new substances with different properties (e.g., rusting iron).

The Periodic Table

• Elements are arranged in groups (vertical columns) and periods (horizontal rows).

• Group Numbering: Main group elements (1-2, 13-18) and transition metals (3-12).

• Groups often share similar chemical and physical properties.

• Elements can be classified as metals, nonmetals, or metalloids.

Example: Sodium (Na) is a metal in group 1; chlorine (Cl) is a nonmetal in group 17.

Chapter 2: Scientific Measurement and Units

Scientific Notation and Metric Units

Understanding and converting between units is essential in chemistry.

• Scientific Notation: Expresses numbers as a product of a coefficient and a power of ten (e.g., ).

• Metric Conversions: 1 kilogram (kg) = 1000 grams (g).

• Use conversion factors to switch between units (e.g., inches to centimeters).

Significant Figures

• Indicate the precision of a measured value.

• Rules for determining significant figures depend on the type of measurement and zeros present.

• When multiplying/dividing, the answer should have as many significant figures as the measurement with the fewest significant figures.

• When adding/subtracting, the answer should have as many decimal places as the measurement with the fewest decimal places.

Example: (2 significant figures)

Chapter 3: Atomic Structure and Electron Configuration

Structure of the Atom

• Atoms consist of protons (positive), neutrons (neutral), and electrons (negative).

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

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

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

Electron Configuration and Orbital Diagrams

• Electrons fill orbitals in order of increasing energy (Aufbau principle).

• Use the periodic table and orbital filling diagrams to determine electron configurations.

• Example: Electron configuration of oxygen:

Chapter 5: Ionic Compounds and Electron Configuration

Ionic Compounds

• Formed by the transfer of electrons from metals to nonmetals.

• Cation: Positively charged ion (metal loses electrons).

• Anion: Negatively charged ion (nonmetal gains electrons).

• Polyatomic ions are ions composed of more than one atom (see Appendix III).

Electron Configuration and Stability

• Atoms gain or lose electrons to achieve a stable electron configuration, often resembling the nearest noble gas.

• Valence electrons are the outermost electrons and determine chemical reactivity.

Naming and Formulas

• Be able to write chemical formulas from names and vice versa.

• Recognize and name common polyatomic ions.

Chapter 6: Covalent Bonding and Lewis Structures

Covalent Bonds and Lewis Structures

• Covalent bonds involve the sharing of electron pairs between atoms.

• Some elements exist naturally as diatomic molecules (e.g., H2, O2).

• Lewis structures represent the arrangement of electrons in molecules.

• Follow the octet rule (8 electrons in the valence shell), with exceptions for expanded octets.

• Be able to identify bonding and nonbonding (lone) pairs of electrons.

Chapter 7: Electronegativity and Bond Types

Electronegativity and Bond Polarity

• Electronegativity: The ability of an atom to attract electrons in a chemical bond.

• Bond type depends on the difference in electronegativity between atoms:

• Be able to distinguish between ionic, polar covalent, and nonpolar covalent compounds.

• Identify which compounds can form hydrogen bonds (e.g., H bonded to N, O, or F).

Appendices

Appendix I: Periodic Table

• Reference for element symbols, atomic numbers, and group/period organization.

Appendix II: Orbital Filling Diagram

• Shows the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p, 4s, 3d, etc.).

Appendix III: Common Polyatomic Ions

Appendix IV: Molecular Geometry

Additional info: This study guide covers foundational topics in General, Organic, and Biochemistry (GOB) Chemistry, including atomic structure, periodic trends, bonding, molecular geometry, and essential skills in measurement and nomenclature. Mastery of these concepts is critical for success in introductory chemistry courses.