Chemistry Chapter 3 Flashcards

Compounds and Chemical Bonds

• Compounds are formed when elements combine, exhibiting properties different from the constituent elements (e.g., Hydrogen + Oxygen = Water).
• Chemical bonds are attractions between atoms that arise from protons’ attraction to electrons.

Types of Chemical Bonds

• Three types of bonding: Ionic, Covalent, and Metallic.
• Ionic bonds occur between metals and nonmetals, involving electron transfer and resulting in charged ions (cations and anions).
• Covalent bonds form between nonmetals through mutual attraction for shared electrons, where electron sharing occurs.

Characteristics of Ionic and Covalent Bonds

• Ionic compounds are characterized by the transfer of electrons, considerable differences in properties from elemental components.
• Covalent bonding involves a balance of attractive forces (between nuclei and electrons) and repulsive forces (within electrons and protons).

Formulas and Representations

• Chemical formulas indicate the composition and stoichiometry of substances (e.g., C2H6O for ethanol).
• Types of chemical formulas: Molecular (exact atom count), Empirical (simplest ratio), Structural (connections between atoms).

Models and Molecules

• Molecular models include ball-and-stick and space-filling models, providing visual representation of molecular structure.
• Diatomic molecules consist of pairs of the same atom (e.g., N2, O2), while polyatomic molecules involve multiple atoms (e.g., P4).

Ionic vs. Molecular Compounds

• Ionic compounds contain metal and nonmetal components, while molecular compounds involve nonmetals connected by covalent bonds.

Predicting and Naming Ionic Compounds

• Ionic compounds can form from combinations of metal, nonmetal, or polyatomic ions, achieving a net charge of zero.
• Common oxidation states: Alkali metals (+1), Alkaline earth metals (+2), Halogens (-1), Aluminum (+3), and varied states for other nonmetals.

Common Polyatomic Ions

• Examples include Acetate (C2H3O2-), Carbonate (CO32-), Hydroxide (OH-), and Nitrate (NO3-), among others.

Naming Conventions

• Ionic compounds with alkali/alkaline earth metals are named using the metal's cation name followed by the nonmetal's anion name in -ide.
• For transition metals, metal oxidation states are indicated with Roman numerals.
• Hydrates involve an ionic compound and water; named using prefixes indicating the number of water molecules.

Naming Hydrate Compounds

• The number of water molecules in hydrates is prefixed (e.g., hexahydrate for six water molecules).

Molecular Compound Naming

• Named based on the most metallic nonmetal first, followed by the second nonmetal with an -ide ending, incorporating prefixes to indicate quantities.

Acids

• Acids release hydrogen ions in water, characterized by a sour taste and low pH values. Examples include hydrochloric acid (HCl).

Determining Molecular Formulas

• To determine molecular formulas, calculate the mole ratio from elemental composition to find the empirical formula.