Chemistry terms starting with N

Negative Deviation Solutions & Colligative Properties Pa Behaviour in which a solution exerts a lower vapour pressure than Raoult's law predicts. p < x p°

Nernst Equation Electrochemistry & Redox V The equation relating a cell's potential to the concentrations of the species involved. E = E° − (RT/nF) ln Q

Net Ionic Equation Stoichiometry & Chemical Reactions Dimensionless An equation showing only the species that actually change during a reaction, with all spectator ions removed. Ag⁺(aq) + Cl⁻(aq) → AgCl(s)

Neutral Salt Acids, Bases & Salts Dimensionless A salt whose aqueous solution has a pH of 7 because neither of its ions hydrolyses appreciably.

Neutral Solution Acids, Bases & Salts mol/L A solution in which the concentrations of hydrogen and hydroxide ions are exactly equal. [H⁺] = [OH⁻] = √Kw

Neutralisation Reaction Stoichiometry & Chemical Reactions kJ/mol The reaction between an acid and a base to produce a salt and water. HA + BOH → BA + H₂O

Neutron Atomic Structure & Periodicity u An electrically neutral subatomic particle found in the nucleus, with a mass slightly greater than that of a proton. m_n = 1.6749 × 10⁻²⁷ kg

Neutron Emission Nuclear & Radiochemistry MeV The direct ejection of a neutron from an extremely neutron-rich nucleus. ᴬ_Z X → ᴬ⁻¹_Z X + ¹₀n

Neutron-to-Proton Ratio Nuclear & Radiochemistry Dimensionless The ratio of neutrons to protons in a nucleus, the principal determinant of its stability and decay mode. N / Z

Nitrile Organic Chemistry Dimensionless A compound containing a carbon–nitrogen triple bond. R–C≡N

Noble Gases Atomic Structure & Periodicity Dimensionless The group 18 elements, whose completely filled valence shells make them exceptionally unreactive. ns² np⁶ (He is 1s²)

Node Atomic Structure & Periodicity Dimensionless A region within an orbital where the probability of finding an electron falls to zero. total nodes = n − 1

Non-Ideal Solution Solutions & Colligative Properties Pa A solution that departs from Raoult's law because interactions between unlike molecules differ from those between like molecules. p ≠ x p°

Normality Solutions & Colligative Properties N (equiv/L) The concentration of a solution expressed as gram equivalents of solute per litre of solution. N = M × n-factor

Nuclear Binding Energy Nuclear & Radiochemistry MeV The energy that would be required to separate a nucleus completely into its individual protons and neutrons. E = Δm c²

Nuclear Chain Reaction Nuclear & Radiochemistry Dimensionless A self-sustaining sequence of fissions in which neutrons released by one event trigger further events. k = neutrons produced / neutrons lost

Nuclear Chemistry Nuclear & Radiochemistry Dimensionless The study of changes that occur in atomic nuclei and of the properties of radioactive substances.

Nuclear Cross Section Nuclear & Radiochemistry barn A measure of the probability that a particular nuclear reaction will occur between a nucleus and an incident particle. σ, measured in barns

Nuclear Fission Nuclear & Radiochemistry MeV The splitting of a heavy nucleus into two lighter nuclei with the release of neutrons and a large amount of energy. ²³⁵U + n → fragments + 2–3n + energy

Nuclear Fuel Enrichment Nuclear & Radiochemistry Dimensionless The process of increasing the proportion of a fissile isotope above its natural abundance.

Nuclear Fusion Nuclear & Radiochemistry MeV The combining of light nuclei into a heavier one, releasing energy. ²H + ³H → ⁴He + n + 17.6 MeV

Nuclear Isomer Nuclear & Radiochemistry MeV A nucleus in a long-lived excited state that decays to its ground state by gamma emission. denoted with m, e.g. ⁹⁹ᵐTc

Nuclear Magnetic Resonance Spectroscopy Analytical Chemistry & Spectroscopy MHz A technique that probes molecular structure using the resonance of atomic nuclei in a strong magnetic field. ν = γB₀ / 2π

Nuclear Reactor Nuclear & Radiochemistry MW A device in which a controlled nuclear chain reaction generates heat for power or produces radioisotopes.

Terms starting with N