General Chemistry: Measurement, Atomic Structure, Nomenclature, and Stoichiometry

Comprehensive vocabulary flashcards covering fundamental chemistry topics: measurements, unit conversions, density, temperature scales, atomic theory, subatomic particles, isotopes, ions, periodic table organization, nomenclature of ionic/molecular compounds and acids, mole calculations, percent composition, and empirical/molecular formula determination.

Measurement

A quantitative observation that consists of two essential parts: a number (which tells comparison) and a unit (which tells scale).

Scientific Notation

A method used to express very large or very small numbers as the product of a number between $1$ and $10$ and an appropriate power of $10$.

Density

The ratio of the mass of a substance to its volume, represented by the formula $\text{Density} = \frac{\text{mass}}{\text{volume}}$, with common units of $\text{g/cm}^3$ or $\text{g/mL}$ for solids and liquids, and $\text{g/L}$ for gases.

Temperature Scales

The three standard systems used to measure temperature: Fahrenheit, Celsius, and Kelvin, related by $T_{\text{K}} = T_{^{\text{o}}\text{C}} + 273$ and $T_{^{\text{o}}\text{F}} = 1.80(T_{^{\text{o}}\text{C}}) + 32$.

Atom

The smallest unit of an element that retains the distinct chemical properties of that element.

Molecule

A discrete particle composed of two or more atoms bound together in a definite arrangement, which can consist of atoms from the same or different elements.

Compound

A pure substance composed of two or more elements combined chemically in definite proportions, exhibiting chemical and physical properties distinct from its constituent elements.

Electron

A negatively charged subatomic particle located outside the atomic nucleus, possessing a charge of $-1.6022 \times 10^{-19 cardinal C}$ ($-1$ relative charge) and a mass of $9.1094 \times 10^{-28 cardinal g}$.

Proton

A positively charged subatomic particle located in the atomic nucleus, possessing a charge of $+1.6022 \times 10^{-19 cardinal C}$ ($+1$ relative charge) and a mass of $1.6726 \times 10^{-24 cardinal g}$.

Neutron

An uncharged subatomic particle located in the atomic nucleus, possessing a mass of $1.6749 \times 10^{-24 cardinal g}$, which is approximately equal to that of a proton.

Plum Pudding Model

An early model of the atom proposed by J. J. Thomson in which negatively charged electrons were envisioned as embedded throughout a uniform sphere of positive charge.

Atomic Number ($Z$)

The number of protons contained in the nucleus of an atom, which uniquely defines the identity of the element.

Mass Number ($A$)

The total number of protons and neutrons in the nucleus of an atom, represented by the equation $A = Z + N$.

Isotopes

Atoms of the same element that have identical atomic numbers (protons) but different mass numbers due to differing numbers of neutrons.

Cation

A positively charged ion that forms when a neutral atom or group of atoms loses one or more electrons.

Anion

A negatively charged ion that forms when a neutral atom or group of atoms gains one or more electrons.

Metalloids

Elements situated along the stair-step line on the periodic table that exhibit physical properties similar to metals but chemical reactivity similar to nonmetals.

Diatomic Molecules

Elements that naturally exist in their elemental form as two-atom molecules: $\text{H}_2$, $\text{N}_2$, $\text{O}_2$, $\text{F}_2$, $\text{Cl}_2$, $\text{Br}_2$, and $\text{I}_2$.

Electrolyte

A substance (including ionic compounds, soluble acids, and bases) that dissociates or ionizes into ions when dissolved in water, producing a solution that conducts electricity.

Nonelectrolyte

A substance (such as most molecular compounds) that dissolves in water without separating into ions and consequently does not conduct electricity.

Ionic Compound

A neutral chemical compound composed of metal cations (or polyatomic cations) and nonmetal anions held together in a crystal lattice structure.

Formula Unit

The relative formula representing the simplest whole-number ratio of cations to anions present in an ionic compound crystal lattice.

Polyatomic Ion

A group of covalently bound atoms that carries a net positive or negative electrical charge (e.g., $\text{NH}_4^+$, $\text{SO}_4^{2-}$).

Oxoanion

A polyatomic anion consisting of one or more oxygen atoms chemically bonded to a central nonmetal or metalloid element.

Procedure for Naming Ionic Compounds

The systematic process of naming ionic compounds by stating the cation name first (including Roman numerals for variable-charge metals), followed by the nonmetal anion root with an '-ide' suffix or the polyatomic ion name.

Binary Molecular Compound

A molecular compound consisting of two different nonmetal elements, named using Greek prefixes to specify the number of atoms of each element.

Acid

A molecular compound containing hydrogen that reacts with water upon dissolving to produce aqueous hydrogen ions ($\text{H}^+(aq)$ or $\text{H}_3\text{O}^+(aq)$).

Procedure for Naming Acids

The set of rules where binary acids are named using the 'hydro-' prefix and '-ic acid' suffix, while oxoacids convert '-ate' oxoanion endings to '-ic acid' and '-ite' endings to '-ous acid'.

Percent Composition by Mass

The percentage by mass of each element in a compound, calculated as $\text{Mass Percent Element} = \frac{\text{Mass of Element}}{\text{Mass of Entire Compound}} \times 100$.

Mole

The SI unit for amount of substance, defined as containing exactly Avogadro's number ($6.022 \times 10^{23}$) of elementary entities, equivalent to the number of atoms in exactly $12 cardinal g$ of carbon-12.

Avogadro's Number

The fundamental constant representing the number of particles in one mole of any substance, equal to $6.022 \times 10^{23 cardinal particles/mol}$.

Molar Mass

The mass in grams of one mole of a substance ($\text{g/mol}$), which has the same numerical value as the average atomic or formula mass of the substance in atomic mass units ($\text{amu}$).

Empirical Formula

The chemical formula of a substance that expresses the simplest whole-number ratio of atoms or ions of each element present.

Molecular Formula

The chemical formula that indicates the exact, actual number of atoms of each element present in a single molecule of a compound.