The Components of Matter - Vocabulary Flashcards

Vocabulary flashcards covering key terms from The Components of Matter notes, including matter types, atomic theory, isotopes, mass concepts, ions, bonding, and chemical nomenclature.

Element

The simplest type of substance with unique properties, consisting of only one type of atom and cannot be broken down into simpler substances by physical or chemical means.

Molecule

A structure that contains two or more atoms chemically bound together and acts as an independent unit.

Compound

A substance formed when two or more elements are chemically combined.

Mixture

A group of two or more elements and/or compounds physically intermingled.

Heterogeneous mixture

A mixture with one or more visible boundaries between components; non-uniform composition.

Homogeneous mixture (Solution)

A mixture with no visible boundaries and a uniform composition; also called a solution.

Aqueous solution

A solution in which water is the solvent.

Filtration

A separation technique that uses particle size differences to separate components, often removing a precipitate.

Crystallization

A separation method based on differences in solubility of components in a mixture.

Distillation

A separation technique based on differences in volatility (tendency to form a gas) of components.

Chromatography

A separation method based on differences in solubility in a solvent versus a stationary phase.

Law of Mass Conservation

The total mass of substances present does not change during a chemical reaction.

Law of Definite (Constant) Composition

A given compound always contains the same elements in the same proportion by mass.

Mass fraction

The ratio of the mass of a component to the total mass of the mixture.

Percent by mass

The mass fraction expressed as a percentage of the total mass.

Law of Multiple Proportions

If elements form more than one compound, the different masses of one element that combine with a fixed mass of the other form small whole-number ratios.

Dalton's Atomic Theory

Matter is made of atoms; atoms are indivisible; atoms of a given element are identical; compounds form from specific ratios of atoms; atoms are conserved in reactions.

Isotopes

Atoms of the same element (same Z) with different numbers of neutrons, giving different mass numbers.

Atomic Number (Z)

The number of protons in the nucleus of an atom.

Mass Number (A)

The total number of protons and neutrons in an atom’s nucleus (A = Z + N).

Neutron

A neutral subatomic particle in the nucleus with mass similar to a proton.

Proton

A positively charged subatomic particle in the nucleus.

Electron

A negatively charged subatomic particle outside the nucleus with much smaller mass than protons/neutrons.

Nucleus

The dense, positively charged center of an atom containing protons and neutrons; electrons orbit around it.

Atomic symbol

The shorthand notation for an element, including symbol, and often its mass and atomic number (A, Z, N).

Isotopes (example)

Atoms of the same element with the same number of protons but different numbers of neutrons (e.g., 28Si, 29Si, 30Si).

Mass Spectrometry

Analytical technique that measures relative masses and abundances of atomic-scale particles.

Isotopic abundance

The relative quantities of each isotope of an element found in nature.

Atomic Mass

The weighted average mass of the naturally occurring isotopes of an element, in atomic mass units.

Atomic mass unit (amu)

A unit defined as 1/12 the mass of a carbon-12 atom; used to express atomic and molecular masses.

Mass of electron (Millikan)

Elementary charge e = 1.602 × 10^-19 C; electron mass approximately 9.11 × 10^-31 kg.

Rutherford’s nuclear model (nucleus)

Discovery that atoms have a tiny, dense, positively charged nucleus; most of the atom is empty space.

Subatomic particles (charges and masses)

Proton: +1e, mass ~1 amu; Neutron: 0e, mass ~1 amu; Electron: −1e, mass ~1/1836 amu.

Ion

A charged species formed by loss or gain of electrons.

Cation

An ion with a positive charge (electrons removed).

Anion

An ion with a negative charge (electrons gained).

Polyatomic ion

A covalently bonded group of atoms that carries an overall charge.

Ionic compound

Compound formed by transfer of electrons from metal to nonmetal; composed of cations and anions.

Binary ionic compound

Ionic compound composed of monatomic cations and monatomic anions.

Roman numeral in ionic names

Used to denote the charge of metals that form more than one possible oxidation state (e.g., iron(III) in Fe2O3).

Prefixes and naming of polyatomic ions

Names of compounds with polyatomic ions follow the ion name; -ide often added to the simple ion; polyatomic ions retain their names (e.g., sulfate, nitrate).

Hydrates

Ionic compounds with a specific number of water molecules attached (e.g., Ba(OH)2·8H2O).

Binary acids

Acids formed from hydrogen and a monoatomic anion; named hydro- + nonmetal root + -ic + acid.

Oxoacids naming

Acids derived from oxoanions; -ate becomes -ic, -ite becomes -ous; include the word acid.

Alkanes

Saturated hydrocarbons containing only carbon and hydrogen; named with root name plus the suffix -ane.

First 10 straight-chain alkanes

Methane, Ethane, Propane, Butane, Pentane, Hexane, Heptane, Octane, Nonane, Decane.

Molecular mass vs Formula mass

Molecular mass is the sum of atomic masses in a molecule; formula mass is used for ionic compounds without discrete molecules.