Matter, Atomic Theory, and Chemical Nomenclature – Lecture Vocabulary

A set of 100 English vocabulary flashcards covering key terms and definitions from the lecture on matter, atomic theory, quantum mechanics, chemical bonding, and nomenclature.

Matter

Anything that occupies space and has mass.

Plasma

The fourth state of matter; an ionized gas occurring naturally in stars.

Solid (state)

Phase of matter with fixed shape and volume, tightly packed particles.

Liquid (state)

Phase with definite volume but shape that adapts to its container.

Gas (state)

Phase that expands to fill its container, particles far apart.

Particle Arrangement in Solids

Tightly packed, ordered configuration of particles.

Particle Arrangement in Liquids

Disordered arrangement with particles close together.

Particle Arrangement in Gases

Totally disordered arrangement; particles widely separated.

Compressibility

Measure of how much a substance’s volume decreases under pressure.

Density

Mass per unit volume of a substance.

Diffusion

Spontaneous mixing of particles from regions of high to low concentration.

Thermal Expansion

Increase in volume of matter when heated.

Physical Change

Change that does not alter a substance’s chemical identity.

Chemical Change

Process that alters the composition or identity of substances.

Physical Property

Characteristic observed without changing chemical identity (e.g., color, melting point).

Chemical Property

Characteristic describing a substance’s ability to undergo chemical change.

Extensive Property

Property that depends on the amount of matter (e.g., mass, volume).

Intensive Property

Property independent of the amount of matter (e.g., density, temperature).

Atom (Democritus concept)

Smallest indivisible particle of matter, termed “atomos.”

John Dalton

Proposed modern atomic theory explaining matter as combinations of atoms.

Law of Definite Proportions

A compound always contains the same elements in the same mass ratio.

Law of Multiple Proportions

Elements can combine in different ratios to form different compounds.

Law of Conservation of Mass

Matter is neither created nor destroyed in chemical reactions.

Nucleus

Dense central core of an atom containing protons and neutrons.

Proton

Positively charged subatomic particle in the nucleus.

Electron

Negatively charged subatomic particle orbiting the nucleus.

Neutron

Electrically neutral particle within the nucleus.

J. J. Thomson

Scientist who discovered the electron.

Robert Millikan

Determined the charge of the electron via the oil-drop experiment.

Ernest Rutherford

Discovered the atomic nucleus and protons through gold-foil experiments.

James Chadwick

Discovered the neutron.

Atomic Number (Z)

Number of protons in an atom; identifies the element.

Mass Number (A)

Total number of protons and neutrons in an atom.

Neutron Count

Calculated as A – Z for a given atom.

Isotope

Atoms of the same element with different mass numbers.

Atomic Mass

Weighted average mass of all naturally occurring isotopes of an element.

Max Planck

Formulated quantum theory: energy emitted in discrete quanta.

Photon

Quantum of light; particle of electromagnetic radiation (Einstein).

Niels Bohr

Explained hydrogen spectrum with quantized electron orbits.

Louis de Broglie

Proposed wave-particle duality of matter.

Heisenberg Uncertainty Principle

Impossible to know both position and momentum of a particle precisely.

Schrödinger Equation

Wave equation describing electron behavior in atoms.

Principal Quantum Number (n)

Defines orbital energy level and size.

Angular Momentum Quantum Number (l)

Determines shape of an atomic orbital.

Magnetic Quantum Number (ml)

Specifies orientation of an orbital in space.

Spin Quantum Number (ms)

Indicates the two possible electron spin orientations (+½ or –½).

Atomic Orbital

Region of space with high probability of finding an electron.

Electron Configuration

Notation showing distribution of electrons among orbitals.

Orbital Diagram

Visual representation of electrons in boxes with arrows indicating spins.

Pauli Exclusion Principle

No two electrons in an atom have the same four quantum numbers.

Hund’s Rule

Electrons occupy degenerate orbitals singly with parallel spins first.

Aufbau Principle

Electrons fill lowest-energy orbitals before higher ones (building-up).

Periodic Table

Chart arranging elements by atomic number and properties.

Periods

Horizontal rows of the periodic table.

Groups

Vertical columns of the periodic table with similar properties.

Lewis Dot Symbol

Chemical symbol surrounded by dots representing valence electrons.

Lewis Stability Concept

Atoms form bonds to achieve a more stable electron configuration (often octet).

Ion

Atom or molecule with a net electric charge.

Cation

Positively charged ion formed by electron loss.

Anion

Negatively charged ion formed by electron gain.

Ionic Bond

Electrostatic attraction between oppositely charged ions.

Covalent Bond

Bond formed by sharing electrons between atoms.

Polar Bond

Covalent bond with unequal electron sharing due to electronegativity difference.

Electronegativity

Ability of an atom to attract shared electrons.

Lewis Structure

Diagram showing bonding and lone pairs in a molecule or ion.

Chemical Formula

Expression indicating the composition of a substance with element symbols and subscripts.

Molecular Formula

Gives the actual number of each type of atom in a molecule.

Structural Formula

Shows how atoms are connected in a molecule.

Empirical Formula

Simplest whole-number ratio of atoms in a compound.

Binary Ionic Compound

Ionic compound composed of two elements (e.g., KBr).

Ternary Ionic Compound

Ionic compound containing three different elements (e.g., LiOH).

Transition-Metal Nomenclature

Uses Roman numerals to denote metal’s oxidation state (e.g., Iron(III)).

Molecular Compound Nomenclature

Uses prefixes (mono-, di-, etc.) to indicate atom counts in covalent compounds.

Acid

Substance that yields H⁺ ions when dissolved in water.

Oxoacid

Acid containing hydrogen, oxygen, and another central element (e.g., HNO₃).

Oxoanion

Anion derived from an oxoacid (e.g., CO₃²⁻ from H₂CO₃).

Base

Substance that yields hydroxide ions (OH⁻) in water.

Hydrate

Compound with a specific number of water molecules attached.

Coordination Compound

Compound consisting of a central metal atom bonded to surrounding ligands.

Coordination Complex

Assembly of a metal ion and its bound ligands acting as a single species.

Chemical Bond

Force holding atoms together in molecules or crystals.

Motion of Particles in Solids

Particles vibrate in fixed positions with minimal freedom.

Motion of Particles in Liquids

Particles move freely relative to each other.

Motion of Particles in Gases

Particles have complete freedom and high velocity.

Shape of Solids

Retain their own shape independent of container.

Shape of Liquids

Assume the shape of their container’s bottom portion.

Shape of Gases

Adopt the shape of the entire container.

Volume of Solids

Definite and fixed volume.

Volume of Liquids

Definite volume that remains constant.

Volume of Gases

Expand to fill the entire container volume.

Diffusion in Solids

Extremely slow; mainly at the surface.

Diffusion in Liquids

Occurs slowly throughout the bulk liquid.

Diffusion in Gases

Rapid mixing of gas molecules.

Thermal Expansion of Solids

Low increase in size with temperature rise.

Thermal Expansion of Liquids

Low but greater expansion than solids on heating.

Thermal Expansion of Gases

High volume increase when heated.

Democritus’s "Atomos"

Ancient idea that matter is composed of indivisible units called atoms.

Dalton Postulate 1

Atoms retain identity during chemical reactions.

Dalton Postulate 2

Elements consist of one kind of atom with identical properties.

Dalton Postulate 3

Compounds form from atoms of two or more elements in fixed ratios.