General Chemistry: Atomic Structure, Chemical Bonding, and Molecular Properties

Comprehensive practice flashcards defining foundational chemistry concepts, periodic trends, bonding classifications, VSEPR geometries, and intermolecular forces.

Ion

An atom or a group of atoms that carries an electrical charge due to an imbalance between the number of protons and electrons.

Cation

A positively charged ion formed when an atom loses one or more electrons, resulting in more protons than electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons, resulting in more electrons than protons.

Polyatomic Ion

A group or clump of multiple atoms bonded together that carries an overall net electrical charge.

Isotope Notation

A notation method showing an element's chemical symbol accompanied by its mass number on the top left, atomic number on the bottom left, and net charge on the top right.

Atomic Number

The number of protons in the nucleus of an atom, identifying the element and written at the bottom left in isotope notation.

Mass Number

The total number of protons plus neutrons in an atom's nucleus, written at the top left in isotope notation.

Electron Configuration

The distribution and arrangement of electrons among the shells, subshells, and orbitals of an atom or ion.

Ionization Energy

The amount of energy required to remove an electron from the outermost shell of an atom or ion.

Core Electrons

Inner electrons that, once their orbitals are fully occupied, shield outer valence electrons from the attractive force of the nucleus.

Valence Electrons

Electrons occupying the outermost shell or energy level of an atom that determine its chemical reactivity and bonding behavior.

VSEPR Theory

Valence Shell Electron Pair Repulsion theory; a model stating that electron pairs in bonds and lone pairs push as far apart as possible to determine three-dimensional molecular geometry.

Linear Molecular Geometry

A molecular geometry formed when two electron groups or bonded atoms surround a central atom, separated by a bond angle of $180^\circ$.

Trigonal Planar Geometry

A molecular geometry where three electron domains surround a central atom in a flat plane with bond angles of $120^\circ$.

Tetrahedral Geometry

A three-dimensional molecular geometry where four bonded atoms surround a central atom with equal bond angles of $109.5^\circ$.

Trigonal Pyramidal Geometry

A three-dimensional molecular geometry where a central atom is bonded to three atoms and carries one lone pair, yielding a bond angle of approximately $107^\circ$.

Bent Molecular Geometry

A non-linear molecular shape resulting from lone pairs repelling adjacent bonds, giving bond angles of approximately $116^\circ$ (three domains) or $104.5^\circ$ to $105^\circ$ (four domains).

Electronegativity

The relative strength or attractive force an atom possesses to draw bonding pairs of electrons toward itself.

Nonpolar Covalent Bond

A covalent bond formed between two atoms with identical or very close electronegativities (difference less than $0.5$) such that bonding electrons are shared evenly.

Polar Covalent Bond

A covalent bond formed between atoms with an electronegativity difference between roughly $0.5$ and $1.7$, causing unequal sharing of electrons and partial electrical charges.

Ionic Bond

A strong electrostatic attraction formed between oppositely charged ions after an electronegativity difference exceeding roughly $1.5$ to $2.0$ causes one atom to completely transfer electrons to another.

Dipole Moment

A vector quantity representing the spatial separation of partial positive ($\delta^+$) and partial negative ($\delta^-$) charges within a bond or polar molecule.

Hydrogen Bonding

A strong intermolecular attraction that occurs when hydrogen is covalently bonded to highly electronegative elements, specifically fluorine, oxygen, or nitrogen.

Dispersion Forces

Weak intermolecular attractive forces present in all molecular substances caused by temporary, fluctuating dipole moments.

Intermolecular Forces

Attractive forces acting between individual molecules that govern physical properties including boiling points, melting points, viscosity, and surface tension.

Cohesion

The intermolecular attractive force pulling molecules of the same liquid toward one another, minimizing the liquid's surface area.

Adhesion

The attractive force operating between molecules of a liquid and the surface of a surrounding container or tube.

Vapor Pressure

The pressure exerted by gas molecules in dynamic equilibrium above their liquid phase inside a closed system.

Miscibility

The property or capacity of two distinct substances or liquids to dissolve and mix together uniformly.

Ideal Gas

A theoretical model of a gas represented by $PV = nRT$, which assumes zero intermolecular forces and negligible particle volume.

Bohr Model

A structural diagram of an atom illustrating protons and neutrons inside a central nucleus with electrons orbiting in defined concentric energy levels.

Atomic Mass Unit

A mass scale where a single proton equals $1\,\text{amu}$, a neutron equals $1\,\text{amu}$, and an electron has a mass of $\frac{1}{2000}\,\text{amu}$.

Lewis Structure

A diagrammatic representation of an atom or molecule that explicitly shows valence electrons as dots and shared bonding pairs as lines.

Octet Rule

The chemical guideline stating that main-group atoms tend to gain, lose, or share electrons until they achieve a stable outer shell of eight valence electrons.

Atomic Radius

The typical size of an atom, which increases going down a group due to added electron shells and decreases from left to right across a period due to increased nuclear charge.

Electron Affinity

A measure of how readily an atom desires to gain an electron to form a negative ion.

Periodic Group

A vertical column of elements on the periodic table sharing identical numbers of valence electrons and exhibiting similar chemical behaviors.

Line Structure

A skeletal shorthand for organic molecules where line vertices and ends represent carbon atoms, lines represent carbon-carbon bonds, and attached hydrogen atoms are implied.

Cis Isomer

A geometric isomer across a non-rotating carbon-carbon double bond in which larger substituent groups are positioned on the same side.

Trans Isomer

A geometric isomer across a non-rotating carbon-carbon double bond in which larger substituent groups are positioned on opposite sides.

Molecular Symmetry

A uniform spatial arrangement of identical outer atoms that allows individual bond dipole vectors to cancel out completely, yielding a nonpolar molecule.