Gen. Chem. Chapter 7 – Flashcards
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| quantum-mechanical model |
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| a model that explains the behavior of absolutely small particles such as electrons and photons |
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| electromagnetic radiation |
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| a form of energy embodied in oscillating electric and magnetic fields |
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| amplitude |
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| the vertical height of a crest (or depth of a trough) of a wave; a measure of wave intensity |
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| wavelength |
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| the distance between adjacent crests of a wave |
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| frequency |
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| for waves, the number of cycles (or complete wavelengths) that pass through a stationary point in one second |
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| electromagnetic spectrum |
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| the range of the wavelengths of all possible electromagnetic radiation |
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| gamma rays |
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| the form of electromagnetic radiation with the shortest wavelength and the highest energy |
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| X-rays |
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| electromagnetic radiation with wavelengths slightly longer than those of that gamma rays |
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| ultraviolet (UV) radiation |
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| electromagnetic radiation with slightly smaller wavelengths than visible light |
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| visible light |
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| those frequencies of electromagnetic radiation that can be detected by the human eye |
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| infrared (IR) radiation |
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| electromagnetic radiation emitted from warm objects, with wavelengths slightly larger than those of visible light |
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| microwaves |
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| electromagnetic radiation with wavelengths slightly longer than those of infrared radiation |
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| radio waves |
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| the form of electromagnetic radiation with the longest wavelengths and smallest energy |
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| interference |
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| the superposition of two or more wave overlapping in space, resulting in either an increase in amplitude (constructive interference) or a decrease in amplitude (destructive interference) |
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| constructive interference |
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| the interaction of waves from two sources that align with overlapping crests, resulting in a wave of greater amplitude |
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| destructive interference |
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| the interaction of waves from two sources aligned so that the crest of one overlaps the trough of the other, resulting in cancellation |
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| diffraction |
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| the phenomena by which a wave emerging from an aperture spreads out to form a new wave front |
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| photoelectric effect |
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| the observation that many metals emit electrons when light falls upon them |
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| photon (quantum) |
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| the smallest possible packet of electromagnetic radiation with an energy equal to hv |
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| emission spectrum |
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| the range of wavelengths emitted by a particular element; used to identify the element |
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| de Broglie relation |
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| the observation that the wavelength of a particle is inversely proportional to its momentum; wavelength = h/mv |
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| complementary properties |
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| those properties that exclude one another, i.e. the more you know about one, the less you know about the other. For example, the wave nature and particle nature are complementary |
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| Heisenberg's uncertainty principle |
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| the principle stating that due to the wave-particle duality, it is fundamentally impossible to precisely determine both the position and the velocity of a particle at a given moment in time |
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| deterministic |
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| a characteristic of the classical laws of motion, which imply that present circumstances determine future events |
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| indeterminacy |
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| the principle that presents circumstances do not necessarily determine future events in the quantum-mechanical realm |
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| orbital |
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| a probability distribution map, based on the quantum mechanical model of the atom, used to describe the likely position of an electron in an atom; also an allowed energy state for an electron |
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| wave function |
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| a mathematical function that describes the wavelike nature of the electron |
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| quantum number |
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| one of four interrelated numbers that determine the shape and energy of orbitals |
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| principal quantum number (n) |
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| an integer that specifies the overall size and energy of an orbital. The higher the quantum number n, the greater the average distance between the electron and the nucleus and the higher its energy |
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| angular momentum number (l) |
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| an integer that determines the shape of an orbital |
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| magnetic quantum number (ml) |
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| an integer that specifies the orientation of an orbital |
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| principal level (shell) |
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| the group orbitals with the same value of n |
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| sublevel (subshell) |
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| those orbitals in the same principle level with the same value of n and l |
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| probability density |
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| the probability (per unit volume) of finding the electron at a point in space as expressed by a three-dimensional plot of the wave function squared |
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| node |
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| a point where the wave function and therefore the probability density and radial distribution function, all go through zero |
