Chapter 3: Atomic Structure Flashcards Preview

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Flashcards in Chapter 3: Atomic Structure Deck (35):
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Electromagnetic radiation

Any form of radiant energy in the electromagnetic spectrum.

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Electromagnetic spectrum

A continuous range of radiant energy that includes Gamma Rays, x-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves.

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Wavelength

The distance from crest to crest or trough to trough on a wave.

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Frequency (v)

The number of crests of a wave that pass a stationary point of reference per second.

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Herts (Hz)

The SI unit of frequency with units of reciprocal seconds: 1 Hz = 1s^-1 = 1 cycle per second (cps)

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Fraunhofer lines

A set of dark lines in the otherwise continuous solar spectrum.

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Atomic emission spectra

Characteristic patterns of bright lines produced when atoms are vaporized in high-temperature flames or electrical discharges.

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Atomic absorption spectra

Characteristic patterns of dark lines produced when an external source of radiation passes through free, gaseous atoms.

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Quantum

The smallest discrete quantity of a particular form of energy.

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Planck constant (h)

The proportionality constant between the energy and frequency of electromagnetic radiation expressed in E=hv; h=6.626x10^-34 J x s

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Quantum theory

A model based on the idea that energy is absorbed and emitted in discrete quantities of energy called quanta.

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Quantized

Having values restricted to whole-number multiples of a specific base value.

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Photon

A quantum of electromagnetic radiation.

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Photoelectric effect

The release of electrons from a material as a result of electromagnetic radiation striking it.

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Threshold frequency

The minimum frequency of light required to produce the photoelectric effect.

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Work function

The amount of energy needed to dislodge an electron from the surface of a material.

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Ground state

The most stable, lowest energy state of a particle.

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Excited state

Any energy state above the ground state.

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Electron transition

Movement of an electron between energy levels.

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Matter wave

The wave associated with any moving particle.

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Standing wave

A wave confined to a given space with a wavelength (lambda) related to the length L of the space by L=(lambda/2), where n is a whole number.

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Node

A location in a standing wave that experiences no displacement.

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Heisenberg uncertainty principle

The principle that one cannot simultaneously know the exact position and the exact momentum of an electron.

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Wave mechanics or quantum mechanics

A mathematical description of the wavelike behavior of electrons and other particles.

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Schrödinger wave equation

A description of how the electron matter wave varies with location and time around the nucleus of a hydrogen atom.

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Wave function (phi)

A solution to the Schrödinger wave equation.

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Orbitals

Defined by the square of the wave function (phi); regions in an atom where the probability of finding an electron is high.

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Quantum number

One of four related numbers that specify the energy, shape, and orientation of orbitals in an atom and the spin orientation of electrons in the orbitals.

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Principle quantum number (n)

A positive integer describing the relative size and energy of an atomic orbital or group of orbitals in an atom.

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Angular momentum quantum number (l)

An integer having any value from 0 to (n-1) that defines the shape of an orbital.

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Magnetic quantum number (m(base l))

Defines the orientation of an orbital in space; an integer that may have any value from -l to +l, where l is the angular momentum quantum number.

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Spin quantum number (m(base s))

Either + 1/2 or -1/2, indicating the spin orientation of an electron.

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Pauli exclusive principle

No two electrons in an atom can have the same set of four quantum numbers.

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Aufbau principle

The method of building. Electron configurations of atoms by adding one electron at a time as atomic numbers increases across the rows of the periodic table.

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Electron configuration

The distribution of electrons among the orbitals of an atom or ion.