Nuclear Chemistry, Atomic Structure, and Coordination Compounds Review

Comprehensive vocabulary flashcards covering basic nuclear chemistry, atomic models, periodic trends, bonding theories, crystal structures, acid-base chemistry, and transition metal complexes based on lecture notes.

Nuclear Chemistry

The study of reactions that involve changes in the atomic nuclei.

Nuclear reaction

A reaction where the structure of the nucleus changes, causing elements to convert from one to another, involving protons, neutrons, and electrons while releasing great amounts of energy.

Isotope

Variations of elements with different numbers of neutrons and different atomic masses.

Belt of Stability

A region on a graph of protons versus neutrons where atoms are stable; a $1:1$ ratio is stable up to $20$ protons, while heavier atoms require ratios of $1:1.5$, $1:1.4$, or $1:1.2$.

Beta decay

A type of radioactive decay occurring when more neutrons than protons are present; a neutron turns into a proton and a beta particle is released.

Alpha decay

A type of radioactive decay occurring when more protons than neutrons are present; a proton turns into a neutron and a positron is released.

Nuclear Fission

A process where a heavy, unstable nucleus divides into smaller nuclei.

Nuclear Fusion

A process involving the combining of small nuclei into one larger nucleus.

Singularity

The really small, hot, and dense zone from which the universe started according to the Big Bang Theory.

Big Bang Nucleosynthesis

The production of light elements ($^{2}H$, $^{3}He$, $^{4}He$, $^{7}Li$) soon after the Big Bang, specifically occurring from elements Helium to Beryllium.

Stellar Nucleosynthesis

The production of elements through nuclear fusion inside a star's core.

Oddo-Harkins Rule

The observation that elements with an even atomic number are more abundant than those with odd numbers, also known as the "odd-even effect."

Iron-peak abundance

The point where nuclear reactions stop because iron ($Fe$) cannot be fused into heavier elements without a large energy input, leading to a drop in abundance after iron.

Supernova Nucleosynthesis

The nucleosynthesis of elements heavier than $Fe$ (such as $Xe$, $Au$, and $Pt$) through neutron capture during the collapse of massive stars.

Heisenberg’s Uncertainty Principle

The principle stating it is impossible to know both the momentum and position of a particle with certainty.

Wave function ($\Psi$)

A mathematical description of an electron exhibiting wave properties, as proposed by Erwin Schrodinger.

Probability density ($\Psi^{2}$)

Proposed by Max Born, it represents the probability of finding a particle in a small space.

Radial nodes

Regions where the wave function intersects the x-axis, indicating zero probability of finding electrons; calculated as $n-l-1$.

Principal quantum number ($n$)

A number related to the size and energy of an orbital and the average distance of the electron from the nucleus.

Angular quantum number ($\ell$)

A number that describes the shape of the orbital, ranging from $0$ to $n-1$.

Effective nuclear charge ($Z_{eff}$)

The actual charge felt by an electron when nuclear charge and repulsive effects from other electrons are taken into account.

Pauli’s Exclusion Principle

The rule stating that no two electrons in an atom can have the same set of four quantum numbers and that an orbital can hold only two electrons with opposite spins.

Hund’s Rule of Maximum Multiplicity

The principle that electrons are placed in orbitals to give the maximum number of parallel spins, filling orbitals singly before pairing.

Aufbau Principle

The guideline that electrons are placed to give the lowest energy to an atom, generally following the $n + l$ rule.

Scandide contraction

A small size difference in elements like $Al$ and $Ga$ or $Si$ and $Ge$ caused by the poor shielding of the $d$ orbital.

Ionization energy

The minimum energy required to remove an electron from a gaseous atom in its ground state.

Electron Affinity

The energy change associated with the addition of an electron to a gaseous atom; more negative values indicate easier acceptance.

Polarizability

The distortion of an electron cloud when an external electric field is applied or another molecule approaches.

Valence Bond Theory (VBT)

A theory describing covalent bonds as the overlap of atomic orbitals, each containing one electron, with the bonded atoms retaining their own orbitals.

Sigma bond ($\sigma$)

A head-to-head bond where electron density is concentrated on the axis joining two nuclei.

Pi bond ($\pi$)

A bond where electron density is not on the axis joining the nuclei, formed by unhybridized $p$ orbitals.

Lattice Energy

The energy required to completely separate one mole of a compound into its gaseous ions, or the energy released when forming one mole of crystalline ionic solid from gaseous ions.

Unit cell

The structural component that, when repeated in all directions, creates a macroscopic crystal; it must be stackable without rotation or reflection.

Octahedral holes

Unoccupied spaces between two triangles of spheres in a close-packed structure; the number of these holes equals the number of spheres ($N$).

Tetrahedral holes

Unoccupied spaces formed by a planar triangle of touching spheres; the number of these holes is twice the number of spheres ($2N$).

Amphoteric

The property of a substance, such as water, that can act as both a Bronsted-Lowry acid and base.

Levelling solvent

A solvent, such as water, in which all strong acids or bases appear to have the same strength (e.g., $HCl$ and $HBr$).

Inductive effects

The way an atom affects the electron distribution of a neighboring atom, often through electronegative atoms stabilizing high electron density regions.

Disproportionation

A redox reaction involving the simultaneous reduction and oxidation of an element, identified on a Latimer Diagram when the potential to the right is greater than the potential to the left.

Pourbaix Diagram

An $E-pH$ diagram showing the thermodynamic stability of species at various potentials and pH levels, featuring corrosion, immunity, and passivation zones.

Coordination Number

The number of donor atoms surrounding a central metal atom in a coordination compound.

Chelating ligand

A polydentate ligand, such as $EDTA$, that can donate more than two electron pairs and is thermodynamically favorable.

Crystal Field Theory (CFT)

A theory treating ligands as point charges to explain how they split the degenerate $d$-orbitals of a metal into different energy levels.

Crystal Field Stabilization Energy (CFSE)

The energy gained by a metal center when $d$-orbital electrons occupy lower-energy orbitals in a ligand field.

Self-assembly

The spontaneous organization of molecules into stable and complex structures without an input of energy.

Host-guest chemistry

The study of complexes where a host structure provides binding sites to selectively interact with a guest molecule or ion via noncovalent interactions.