Nuclear Chemistry and Periodic Trends

Vocabulary flashcards covering core concepts of nuclear chemistry (reactions, decay modes, fission, and fusion) and the periodic table (families, elemental properties, and periodic trends).

Radiation

The spontaneous emission of energy and particles by atoms of certain elements when producing new elements.

Alpha Decay

A type of nuclear reaction involving the release of an alpha particle ($^4_2\alpha$ or Helium atom), resulting in a lighter daughter nuclide.

Beta Decay

A type of nuclear reaction involving the release of a beta particle ($e^-$ or $^0_{-1}\beta$).

Positron Decay / Emission

A nuclear reaction characterized by the release of a positron particle ($^0_{+1}\beta$) from an unstable nucleus.

Electron Capture

A nuclear process where an unstable nucleus gains a beta particle ($^0_{-1}e$).

Nuclear Fission

The splitting of a heavy, unstable nucleus into two nuclei with smaller mass numbers, releasing enormous amounts of energy.

Nuclear Fusion

The combining of two light nuclei to form a heavier, more stable nucleus, releasing more energy per gram than fission.

Transmutation

A change in the identity of a nucleus as a result of a change in the number of protons.

Half-Life

The time required for half of the atoms in any given quantity of a radioactive isotope to decay.

Period

A horizontal row on the periodic table where each row corresponds to an energy level.

Group / Family

A vertical column on the periodic table containing elements that share similar chemical and physical properties.

Metals

Elements that are good conductors, solid at room temperature (except $\text{Hg}$), have high luster, reflect light, and are both ductile and malleable.

Ductile

The physical property of a metal describing its ability to be drawn into wire.

Malleable

The physical property of a metal describing its ability to be hammered into thin sheets.

Nonmetals

Elements that are mostly gases at room temperature, poor conductors, brittle, non-ductile, and exhibit properties that vary more than metals.

Metalloids

Elements with a metallic appearance that are only semi-conductive and can form alloys with metals.

Alkali Metals

Group 1 elements possessing 1 valence electron, characterized by low density, softness, low melting and boiling points compared to other metals, and high reactivity with water.

Alkaline Earth Metals

Group 2 elements possessing 2 valence electrons, characterized by a shiny silvery-white color, relatively low density, melting point, and boiling point, and being somewhat reactive at STP.

Halogens

Group 17 nonmetals having 7 valence electrons that need 1 valence electron for a full octet, making them highly reactive with low boiling and melting points.

Noble Gases

Group 18 elements containing 8 valence electrons (except $\text{He}$) that are colorless, odorless, inert gases with a full outer shell and high stability.

Transition Metals

Elements characterized by the presence of electrons in the d sublevel that are not very reactive.

Lanthanide Series

Inner transition metals located at the bottom of the periodic table characterized by high melting and boiling points, high reactivity, and burning easily in air.

Actinide Series

Inner transition metals located at the bottom of the periodic table used in nuclear power that are all radioactive with no stable isotopes.

Atomic Radius

A measure of atomic size defined as half the distance from the nucleus of one atom to the nucleus of an identical atom.

Coulombic Attraction

The attraction between positive and negative charges (protons and electrons), which increases as particles get closer, resulting in a smaller atom.

Effective Nuclear Charge ($Z_{\text{eff}}$)

The net positive charge experienced by an electron, represented by the formula $Z_{\text{eff}} = Z - S$, where $Z$ is nuclear charge (protons) and $S$ is shielding electrons (core electrons).

Electronegativity

The tendency of an atom to attract electrons, which increases with smaller atomic size (more coulombic attraction, less shielding) and more protons (more attractive force).

Shielding

A phenomenon where inner energy level electrons cause repulsion between the outer electrons and the protons in the nucleus, increasing with more energy levels or larger atoms.

Ionization Energy

The minimum amount of energy required to remove the outermost electron from an atom.

First Ionization Energy

The amount of energy required to remove the first electron from an atom.

Cation

A positive ion formed when an atom with fewer than 4 valence electrons loses all its valence electrons; cations are smaller than their parent neutral atom.

Anion

A negative ion formed when an atom with more than 4 valence electrons gains electrons to achieve an octet of 8; anions are larger than their parent neutral atom.