General Chemistry: Molecules and Compounds

Flashcards covering key definitions and nomenclature rules for molecules and compounds in General Chemistry, including classifications of substances, chemical formulas, atomic theory, bonding types, and naming conventions for ionic, covalent, and acid compounds.

Atomic Elements

Pure substances that exist in nature with single atoms as their basic units (e.g., Na, Ne, K, Mg).

Molecular Elements

Pure substances that do not normally exist as single atoms, but as molecules—two or more atoms of the element bonded together (e.g., O2, H2, N2, P4, S8).

Diatomic Elements

Seven specific elements that exist as molecules composed of two atoms: H2, N2, O2, F2, Cl2, Br2, and I2.

Molecular Compounds

Pure substances consisting of two or more different atoms bonded together to form molecules (e.g., H2O, CO2).

Ionic Compounds

Pure substances composed of oppositely charged ions held together by electrostatic forces, forming a crystal lattice (e.g., NaCl).

Law of Multiple Proportions

States that when two elements combine to form more than one compound, the ratios of the masses of the second element that combine with a fixed mass of the first element are small, whole numbers (e.g., AB, AB2, AB3).

Structural Formula

A chemical formula that conveys the type, actual number, and arrangement of atoms in a molecule, showing how atoms are bonded to each other with lines representing covalent bonds.

Molecular Formula

A chemical formula that conveys the actual type and number of elemental atoms in a compound, but not their arrangement or bonding.

Empirical Formula

A chemical formula that conveys the simplest whole-number (relative) relationship of atom to atom in a molecule, providing the least amount of information about the compound.

Ball-and-Stick Molecular Model

A visual representation of a molecule where atoms are depicted as balls and chemical bonds as sticks, reflecting the molecule's shape.

Space-Filling Molecular Model

A visual representation of a molecule where atoms fill the space between each other to represent how a molecule might appear if scaled to visible size.

Mass Percent Composition

The percentage by mass of each element in a compound, used as a conversion factor to relate the mass of an element to the mass of the compound.

Combustion Reactions ( Empirical Formula Determination)

Chemical reactions, typically involving organic compounds (hydrocarbons or carbohydrates) reacting with oxygen, used to produce CO2 and H2O, which can then be analyzed to determine the empirical formula of the original compound.

Chemical Bonds

Forces that hold atoms together in compounds, resulting from attractions between the charged particles (electrons and protons) that compose atoms.

Ionic Bonds

Chemical bonds that occur between a metal and a nonmetal, involving the transfer of electrons from the metal to the nonmetal, creating oppositely charged ions that attract each other.

Cation

A positively charged ion, formed when a metal atom loses one or more electrons.

Anion

A negatively charged ion, formed when a nonmetal atom gains one or more electrons.

Covalent Bonds

Chemical bonds that occur between two or more nonmetals, where atoms share electrons between them to compose a molecule.

Molecular Compounds (Covalent Compounds)

Chemical compounds formed by covalent bonds where electrons are shared between nonmetal atoms.

Type 1 Ionic Compounds

Ionic compounds containing a metal whose charge is invariant from one compound to another (e.g., Alkali metals 1+, Alkaline earth metals 2+, Zinc 2+, Aluminum 3+, Silver 1+).

Type 2 Ionic Compounds

Ionic compounds containing a metal that can vary in charge from one compound to another (e.g., transition metals and p-block metals like Iron, Copper, Tin, Lead).

Naming Type 1 Ionic Compounds

Named by the cation name followed by the base name of the anion with an '-ide' suffix (e.g., NaCl is sodium chloride).

Naming Type 2 Ionic Compounds

Named by the cation name, followed by its charge in Roman numerals in parentheses, and then the base name of the anion with an '-ide' suffix (e.g., FeCl3 is iron(III) chloride).

Polyatomic Ions

Ions composed of two or more atoms covalently bonded together that carry a net charge (e.g., SO4^2- sulfate, NH4^+ ammonium, NO3^- nitrate).

Hydrates

Ionic compounds that contain a specific number of water molecules associated with each formula unit, indicated by a dot notation in the chemical formula (e.g., MgSO4 • 7H2O).

Naming Covalent Compounds (Binary)

Generally, a prefix is used for the first element (unless mono-), followed by its name, then a prefix for the second element, followed by the base name of the second element with an '-ide' suffix (e.g., CO2 is carbon dioxide, N2O is dinitrogen monoxide).

Common Prefixes for Covalent Naming

mono=1, di=2, tri=3, tetra=4, penta=5, hexa=6, hepta=7, octa=8.

Binary Acids

Acids composed of hydrogen and one other nonmetal element, typically named with the prefix 'hydro-', the base name of the nonmetal, and the suffix '-ic acid' (e.g., HCl is hydrochloric acid).

Oxyacids

Acids that contain hydrogen, oxygen, and one other element, named based on the oxyanion: '-ate' suffix becomes '-ic acid' and '-ite' suffix becomes '-ous acid' (e.g., H3PO4 is phosphoric acid, H2SO3 is sulfurous acid).