General Chemistry: Atomic Theory, Forces, and Energy Flashcards

Vocabulary flashcards covering atomic theory development, scientific models, fundamental forces, energy principles, and intermolecular interactions based on general chemistry lecture notes.

Scientific Law

A statement that describes a natural phenomenon or what happens in a system without necessarily explaining why.

Scientific Theory

The best explanation of existing information that explains how or why a phenomenon occurs, allows testable predictions, is falsifiable, and can change over time.

Atomic Force Microscope

An imaging instrument used as evidence for atoms that can visualize surfaces at the atomic level, showing features such as carbon arranged in a hexagon.

Scanning Tunneling Microscope

An instrument that provides experimental evidence for the existence of atoms by imaging surfaces at the atomic scale.

Element

A pure substance consisting of only one type of atom, ordered on the periodic table with $91$ or $98$ naturally occurring types.

Molecule

A chemical species consisting of a group of $2$ or more atoms bonded together.

Compound

A chemical substance composed of $2$ or more different elements combined together.

Billiard Ball Model

John Dalton's atomic model stating that elements consist of identical atoms with equal mass, atoms of different elements differ, compounds contain $2$ or more atoms, and chemical reactions involve atom reorganization.

Plum Pudding Model

J.J. Thomson's atomic model featuring embedded negatively charged electrons (particles lighter than hydrogen atoms) distributed within a positive sphere, discovered using cathode ray experiments.

Nuclear Model of the Atom

Ernest Rutherford's atomic model establishing that the atom is mostly empty space with a small, dense, positively charged nucleus at its center.

Alpha Particle

A positively charged particle composed of $2$ protons and $2$ neutrons (a helium nucleus) emitted by radioactive elements.

Scientific Model

A physical or mental representation—such as a drawing, graph, or equation—that helps make sense of scientific phenomena and yields testable, quantifiable predictions.

Gravity

An attractive force mediated by gravitational fields that acts between any $2$ or more objects possessing mass, described by $F \text{ is proportional to } \frac{M_1 M_2}{r^2}$.

Electromagnetic Force

A fundamental force mediated by electric and magnetic fields that acts between charged particles at a distance and can be both attractive and repulsive.

Strong Nuclear Force

A short-range fundamental interaction occurring between objects composed of quarks.

Weak Nuclear Force

A short-range fundamental interaction occurring between elementary particles.

Isotope

Atoms of the same element that have a variance in their number of neutrons.

Electrostatic Force

The force between charged particles described by $F \text{ is proportional to } \frac{q_1 q_2}{r^2}$, where like charges repel and opposite charges attract.

Joule

The SI unit of energy, defined as $\text{kg}\text{m}^2\text{s}^{-2}$, where $1\text{ Calorie} = 4.184\text{ J}$.

System

The specific part of the universe selected for study when analyzing energy changes.

Surroundings

Everything in the universe outside of the defined system being studied.

First Law of Thermodynamics

The principle stating that energy is conserved and never lost; it can only be transferred between objects or transformed between forms.

Kinetic Energy

The energy of an object associated with motion, given by the formula $E_k = \frac{1}{2} m v^2$.

Potential Energy

The energy based on the position of a system of objects within a field, requiring a field and $2$ or more interacting objects.

London Dispersion Forces

Intermolecular forces present in all neutral atoms and molecules caused by temporary fluctuations in electron density that induce dipoles in adjacent molecules.

Van der Waals Radius

One-half the distance between two non-bonded atoms at their potential energy minimum at equilibrium.

Polarizability

The ease with which the electron cloud of a particle can be distorted (described as floppier), which increases with particle size and results in stronger London dispersion forces.

Covalent Bond

A permanent bond formed within a molecule between atoms, where breaking the bond requires energy and forming the bond releases energy.

Helium Interaction Energy Curve

A plot showing potential energy and kinetic energy as a function of distance as two helium atoms approach each other, reaching a potential energy minimum at equilibrium before electron cloud repulsion dominates at very short distances.