Unit 1: The Northern Lights & Atomic Chemistry Vocabulary

A comprehensive vocabulary flashcard set covering key terms, definitions, and concepts from Unit 1: The Northern Lights, including matter classification, atomic structure, subatomic particles, spectra, and forces.

Element

The simplest type of a pure substance that cannot be broken down into anything simpler using ordinary physical or chemical methods.

Compound

A pure substance made by chemically combining two or more different elements in a specific fixed ratio, forming a new substance with distinct properties.

Mixture

A combination of two or more substances that are physically blended together but not chemically joined, retaining their individual properties.

Homogeneous Mixture

A mixture that is uniformly blended throughout, where individual components are evenly distributed and cannot be distinguished visually.

Heterogeneous Mixture

A mixture with a non-uniform composition, containing visually distinct parts or layers that are not evenly distributed.

Physical Properties

Characteristics of a substance that can be observed or measured without altering its chemical composition or changing it into a new substance.

Chemical Properties

Characteristics of a substance that describe its ability to undergo chemical reactions and change into distinct new substances.

Filtration

A physical separation technique used to separate an insoluble solid from a liquid mixture using a porous filter medium.

Proton ($p^+$)

A positively charged subatomic particle found in the nucleus of an atom, possessing a mass of approximately $1\,amu$.

Neutron ($n^0$)

A neutral subatomic particle located in the nucleus of an atom, possessing a mass of approximately $1\,amu$.

Electron ($e^-$)

A negatively charged subatomic particle located outside the nucleus in principal energy levels, with negligible mass.

Atomic Number ($Z$)

The total number of protons in the nucleus of an atom, which uniquely identifies the element.

Atomic Mass ($A$)

The total mass of an atom, calculated as the combined sum of its protons and neutrons.

Net Charge ($q$)

The overall electrical charge of an atom or ion, calculated as the number of protons minus the number of electrons.

Ion

An atom or group of atoms that has gained or lost one or more electrons, resulting in a net positive or negative charge.

Isotope

Atoms of the same element that contain the same number of protons but different numbers of neutrons, resulting in different mass numbers.

Bohr Model

A structural model of an atom that depicts electrons orbiting a central nucleus containing protons and neutrons in discrete principal energy levels.

Principal Energy Levels (PELs)

The fixed electron shells or orbits located around an atomic nucleus where electrons reside.

Ground State

The most stable, lowest-energy arrangement of electrons in an atom or ion.

Excited State

An unstable state of an atom achieved when electrons absorb energy and jump to higher principal energy levels.

Continuous Spectrum

An uninterrupted rainbow display showing all visible wavelengths of light without gaps, produced by hot, dense light sources.

Absorption Spectrum

A continuous spectrum containing dark line gaps where specific wavelengths of light have been absorbed by cooler gas atoms.

Emission Spectrum

A pattern of distinct bright lines of color emitted at specific wavelengths as excited electrons relax back to lower energy levels.

Coulombic Force

The electrostatic force of attraction or repulsion between charged particles, described by $F \propto \frac{q_1 q_2}{d^2}$.

Strong Nuclear Force

The powerful attractive fundamental force that binds protons and neutrons together within the nucleus, overcoming electrostatic repulsion at short distances.

Percent Composition by Mass

The percentage of a substance's total mass that comes from a specific part, calculated as $\left(\frac{\text{mass of part}}{\text{mass of whole}}\right) \times 100\%$.

Phenomenon

An observable fact or event in nature that can be scientifically studied and investigated.