CHM 122 – Nuclear, Coordination, and Organic Chemistry Essentials

50 English vocabulary-style flashcards covering radioactivity, nuclear chemistry, coordination chemistry, and fundamental organic concepts for CHM 122 Exam #4.

Alpha radiation (α)

Emission of a helium nucleus (⁴₂He); +2 charge, very low penetration, stopped by paper.

Beta radiation (β⁻)

Emission of a high-energy electron (₀₋₁e); –1 charge, moderate penetration, stopped by aluminum.

Positron emission (β⁺)

Release of an antielectron (₀₊₁e); +1 charge, converts a proton to a neutron inside the nucleus.

Gamma radiation (γ)

High-energy photon with no mass or charge; very high penetration requiring lead or concrete shielding.

Half-life (t₁⁄₂)

Time required for one-half of a radioactive sample to decay.

Radiometric dating

Age-determination method that compares parent-to-daughter isotope ratios (e.g., Carbon-14 dating).

Belt of stability

Region on an N/Z plot where nuclides are stable; outside it, nuclei undergo radioactive decay.

Beta decay

Radioactive process where a neutron converts to a proton, emitting a β⁻ particle and an antineutrino.

Electron capture

Nuclear process in which an inner orbital electron is captured by the nucleus, turning a proton into a neutron.

Nuclear fission

Splitting of a heavy nucleus into lighter nuclei with release of neutrons and large amounts of energy.

Nuclear fusion

Combining light nuclei (e.g., deuterium + tritium) to form a heavier nucleus and release even more energy than fission.

Technetium-99m

6-hour metastable isotope emitting γ-rays; widely used in diagnostic imaging due to short half-life.

Iodine-123

Thyroid-imaging γ-emitter with ~13-hour half-life; limits radiation dose to patient.

Iodine-131

β and γ emitter (t₁⁄₂ ≈ 8 d) used for thyroid treatment and imaging.

Mass defect

Difference between summed nucleon masses and actual nuclear mass; represents missing mass converted to energy.

Nuclear binding energy

Energy equivalent (E = mc²) of the mass defect that holds the nucleus together.

Iron-56 stability

Nuclide with one of the highest binding energies per nucleon, making it especially stable.

Coordination compound

Substance consisting of a central metal ion bonded to surrounding ligands, written in brackets.

Ligand

Molecule or ion that donates a lone pair to a metal center in a coordination complex.

Coordination sphere

Metal ion plus its directly bonded ligands, enclosed in square brackets in formulas.

Counterion

Ion outside the coordination sphere that balances the charge of the complex ion.

Anionic ligand

Negatively charged ligand named with “-o” ending, e.g., chloro (Cl⁻), cyano (CN⁻).

Neutral ligand

Uncharged ligand with special names (e.g., NH₃ = ammine, H₂O = aqua).

Coordination number

Number of ligand donor atoms directly attached to the central metal ion.

Monodentate ligand

Ligand that attaches to the metal through a single donor atom (e.g., Cl⁻, NH₃).

Bidentate ligand

Ligand binding through two donor atoms, forming a five-membered chelate ring (e.g., en, C₂O₄²⁻).

Hexadentate ligand

Ligand that binds through six donor atoms, e.g., EDTA⁴⁻, creating highly stable complexes.

Chelate effect

Enhanced stability of complexes containing polydentate ligands due to favorable entropy.

Ionization isomer

Structural isomer where counterion and ligand exchange positions inside or outside the coordination sphere.

Linkage isomer

Structural isomer in which a ligand binds the metal through different donor atoms (e.g., SCN⁻ via S or N).

Geometric isomer

Stereoisomer differing in ligand positions (cis/trans) within the coordination geometry.

Optical isomer

Non-superimposable mirror-image (chiral) complexes that rotate plane-polarized light.

Valence Bond Theory (VBT)

Model describing metal-ligand bonds via hybridization of metal atomic orbitals.

d²sp³ hybridization

Octahedral metal orbital set formed by two d, one s, and three p orbitals; example [Fe(CN)₆]³⁻.

Crystal Field Theory (CFT)

Electrostatic model explaining d-orbital energy splitting caused by surrounding ligand point charges.

t₂g orbitals

Lower-energy trio of d-orbitals in an octahedral field (dxy, dxz, d_yz).

e_g orbitals

Higher-energy pair of d-orbitals in an octahedral field (dz², dx²–y²).

Spectrochemical series

Ranking of ligands by field strength from weak (I⁻, Br⁻) to strong (CN⁻, CO).

Paramagnetic

Substance with unpaired electrons; attracted to an external magnetic field.

Diamagnetic

Substance with all electrons paired; weakly repelled by a magnetic field.

Hydrocarbon

Organic molecule composed solely of carbon and hydrogen atoms.

Alkane

Saturated hydrocarbon containing only single σ bonds; general formula CₙH₂ₙ₊₂.

Alkene

Unsaturated hydrocarbon with at least one C=C double bond; ends with suffix “-ene.”

Alkyne

Unsaturated hydrocarbon containing a C≡C triple bond; ends with suffix “-yne.”

Arene

Aromatic hydrocarbon based on a benzene ring; exhibits resonance stabilization.

Functional group

Specific atom group conferring characteristic reactivity (e.g., –OH, –COOH, –NH₂).

sp³ hybridization

Tetrahedral orbital mixing producing four equivalent σ-bond orbitals (e.g., in methane).

Addition reaction (alkene)

Reaction where atoms add across a C=C bond, converting it to single bonds (e.g., hydrogenation).

Radical halogenation

Free-radical substitution where Cl₂ or Br₂ replaces an H on an alkane under light/heat.

Sigma (σ) bond

Strong covalent bond formed by head-on orbital overlap; allows free rotation around the bond axis.