Chapter 12 Flashcards
Ground state
The lowest energy state of an atom or molecule.
Excited state
States with more energy than the ground (lowest energy level) in an atom or molecule.
Base Peak
The most intense peak in the mass spectrum.
Parent Peak
The peak corresponding to the complete molecule – usually the highest mass peak in the spectrum.
Emission
When an electron in an excited energy state (excited state) returns to the a lower energy state, the transition energy is emitted as light.
Absorption
In spectroscopy, it is the absorption or uptake of light by a substance, accompanied by an increase in the energy of the molecules or atoms of the substance. When electrons become excited from a lower to a higher energy state by absorbing light energy.
Mass-to-charge
The measured mass as a ratio to its charge.
Alpha Emission
The ejection of a helium nucleus, containing two neutrons and two protons, from a radioactive nucleus to form a new atom that is four mass units lighter and shifted two
elements to the left in the periodic table.
Antibonding
A type of chemical bonding that inhibits bonding between atoms and whose energy increases as atoms are brought closer together, resulting in a net repulsion between the atoms.
Color
The way that our eyes and brain perceive different wavelengths of light in the visible range.
Atomic Number
The number of protons in the nucleus of an atom.
Beta Emission
The emission of an electron from a radioactive nucleus.
Beta Emission
The emission of an electron from a radioactive nucleus.
Carbon Cycle
The process whereby carbon is exchanged between living and non-living components in a cyclic arrangement.
Frequency
The number of waves that pass a fixed point per unit of time.
Detector
An instrument, or part of an instrument, designed to detect the presence of electromagnetic radiation or radioactivity.
Emission
The giving off of electromagnetic radiation or radioactivity as an atom or molecule goes from a higher to a lower energy state.
Gamma Emission
The emission of a high-energy photon of electromagnetic radiation in the gamma ray region from a radioactive nucleus
Gas Chromatography
A for of chromatography, used for separating mixtures into its individual components, that uses a gas as the mobile phase.
Isotope
Two or more atoms with the same number of protons but different numbers of neutrons.
Infrared Spectroscopy
The measurement of the absorption of light between about 500 to 1500 cm1 that causes quantized vibrations in molecules.
Half-life
The amount of time necessary for one-half of the original sample to change, decompose or decay away.
Heisenberg Uncertainty Principle
The principle that states that we can never know
simultaneously both the position and the momentum of an object with complete certainty.
Ground State
The lowest energy state of an atom or molecule.
Radioactivity
The spontaneous emission of particles and/or electromagnetic radiation in nuclear decay.
Mass Spectrometry
An instrumental method that separates ionized, gas-phase molecules and molecular fragments by their masses and records the distribution of the observed masses in a
mass spectrum.
Radiocarbon Dating
The analytical method that is used for determining the age of once living, carbon-containing materials based upon the amount of radioactive carbon-14 measured in the
sample.
Radioactivity
The spontaneous emission of particles and/or electromagnetic radiation in nuclear decay.
Radioactive Decay
The disintegration or unstable nuclei with the emission of particles and/or electromagnetic radiation.
Atomic Mass (weight)
The mass of an atom that is expressed in the standard unit of atomic mass units (amu): approximately equal to the number of protons and neutrons in the atom.
Mass-to-Charge Ratio (m/e or sometimes m/z)
The relationship between mass and charge given by
the equation: m/e = H2r2/2V. Typically, this is the mass measurement in a mass spectrum.
Molecular Formula
The chemical formula that shows the number and kind of each atom in a molecule.
Mobile Phase
In chromatography, the component that moves the solute past a fixed medium.
Quantization
The act of restricting or limiting the possible values that a value may have to a finite set, usually determined by a set of rules described in quantum mechanics.
Molecular Ion - See “Parent Ion”
Parent Ion – The peak in the mass spectrum corresponding to the complete molecule, usually the
highest mass peak in the spectrum
Molecular Weight -
The mass of a molecule that is expressed in the standard unit of atomic mass units (amu). Determined by the sum of the atomic masses of all of the atoms that make up the
molecule.
Retention Factor (Rf)
A measure of the degree of interaction of a substance in chromatography with the stationary phase. Determined by dividing the distance the substance traveled by the
distance the mobile phase traveled during a period of time.
Neutron Activation Analysis
The analytical method that measures the characteristic energy emission from atoms in a sample after bombardment with neutrons to determine the atomic
composition of the sample.
Neutron Activation Analysis
The analytical method that measures the characteristic energy emission from atoms in a sample after bombardment with neutrons to determine the atomic
composition of the sample.
Spectroscopy
The study of the interaction of electromagnetic radiation with matter as a function of its wavelength or frequency.
Electron Impact Ionization
The ejection of an electron from an atom or molecule caused by the impact of a high energy electron.
Stationary Phase
In chromatography, the component that remains fixed (does not move) during the separation.
Ultraviolet-Visible Spectroscopy
The measurement of absorptions of light between about 150 and 750 nm by substances.
Visible light
Electromagnetic radiation that can be detected by the human eye, typically from between 280 nm to 750 nm.
Wavelength
The distance measured between like points of successive waves, such as the distance between the crest of one wave to the crest of the following wave.
Nuclide
A type of atom that is defined by its number of protons and neutrons and its quantum state.
Electromagnetic radiation
Radiation that is made up of perpendicular electrical and magnetic waves that oscillate as they moves through space.
Functional Group
The part of a molecule that defines its chemical structure and is responsible for a characteristic set of reactions.
