Atomic Structure, Radioactivity, and the Mole Vocabulary Flashcards

Vocabulary flashcards covering atomic structure, subatomic particles, isotopes, Rutherford's experiment, mole conversions, radioactive decay types, nuclear fission, fusion, and half-life.

Radioactive Decay

The spontaneous disintegration of a nucleus accompanied by the emission of particles, electromagnetic radiation, or both.

Transmutation

The transformation of one element into another caused by a change in the number of protons.

Nucleons

The particles located within the atomic nucleus, specifically protons and neutrons.

Nuclide

Any atom of a specific isotope, characterized by the composition of its nucleus.

Nuclear Symbol Notation

A system for representing a nuclide using the element symbol accompanied by its mass number as a superscript and its atomic number as a subscript in front of the symbol.

Hyphen Notation

A method of representing a nuclide by writing the name of the element followed by a hyphen and its mass number, such as cesium-133.

Alpha Radiation

Radioactive emission of an alpha particle (${}_{2}^{4}\text{He}^{2+}$), which reduces the atomic number of the nucleus by $2$ and the mass number by $4$, and can be blocked by paper.

Beta Radiation

Radioactive decay involving the emission of a beta particle (${}_{-1}^{0}e$) formed when a neutron breaks down into a proton and an electron, increasing the atomic number by $1$ without changing the mass number; blocked by lead or glass.

Gamma Radiation

High-energy electromagnetic radiation with higher energy than X-rays that is emitted alongside alpha or beta particles and possesses no mass or charge.

Positron Emission

A nuclear decay process that emits a positron (${}_{+1}^{0}e$), a particle with the mass of an electron but a positive charge, decreasing the atomic number by $1$ while keeping the mass number unchanged.

Electron Capture

A nuclear reaction in which an inner electron is captured by the nucleus and combines with a proton to form a neutron, decreasing the atomic number by $1$ while leaving the mass number unchanged.

Mole

The amount of a substance that contains the same number of particles as exactly $12\,\text{g}$ of carbon-12.

Avogadro's Number

The number of representative particles contained in exactly one mole of a substance, defined as $6.022 \times 10^{23}\text{ particles}$.

Molar Mass

The mass in grams of one mole of a substance ($\text{g} = 1\,\text{mole}$), which is numerically equivalent to the atomic mass taken from the periodic table.

Mole Highway

A conversion route showing how to convert between particle count, moles, and mass using Avogadro's number ($6.022 \times 10^{23}\text{ particles} = 1\,\text{mole}$) and molar mass.

Half-life

The time required for one-half of the initial amount of a radioactive nuclide present at any given time to undergo decay.

Nuclear Fission

The process in which a heavy nucleus splits into stable, medium-mass nuclei, releasing energy and additional neutrons that can induce a continuous chain reaction.

Nuclear Fusion

A nuclear process occurring at extremely high temperatures in stars where low-mass nuclei fuse together to form a heavier, stable nucleus, releasing large quantities of energy.

Atomic Number

The total number of protons in the nucleus of an atom, designated as $Z$, which establishes the identity of an element and equals the electron count in a neutral atom.

Mass Number

The total sum of protons and neutrons contained in an atomic nucleus, designated as $A$.

Isotopes

Atoms of the same element that contain equal numbers of protons (same atomic number) but differing numbers of neutrons, resulting in distinct mass numbers.

Atomic Mass Unit

A unit of mass defined as exactly $\frac{1}{12}$ of the mass of a carbon-12 atom, approximately equivalent to the mass of a single proton or neutron.

Average Atomic Mass

The weighted average of the atomic masses of all naturally occurring isotopes of an element.

Rutherford's Gold Foil Experiment

A 1910 experiment conducted by Ernest Rutherford, Hans Geiger, and Ernest Marsden that demonstrated atoms consist mostly of empty space surrounding a small, dense, positively charged nucleus.

Proton

A subatomic particle located in the nucleus with a charge of $+1$, a relative size of $1$, and a mass $1840$ times that of an electron, discovered by Ernest Rutherford et al. (1914–1917).

Neutron

A neutral subatomic particle located within the nucleus with a charge of $0$ and a relative size of $1$, discovered by James Chadwick in 1932.

Electron

A subatomic particle positioned outside the atomic nucleus with a charge of $-1$ and a relative size of $\frac{1}{1840}$.