Quantum Theory and the Atom

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Atomic Emission Spectrum Noun

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[uh-tom-ik i-mish-uhn spek-truhm]

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Atomic Emission Spectrum

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A discontinuous spectrum of specific light frequencies produced when an atom's electrons transition from higher to lower energy levels.

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Example: When an element like sodium is energized, it emits light only at specific colors, creating a unique pattern of lines like a fingerprint.

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Ground State Noun

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[ground stayt]

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Ground State

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The lowest allowable energy state of an atom, where it is most stable and its electrons occupy the lowest energy levels.

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Example: This diagram shows that the Ground State (n=1) is the lowest possible energy level for an electron in an atom.

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Excited State Noun

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[ek-sy-ted stayt]

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Excited State

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A state where an atom has higher potential energy than its ground state after its electrons gain energy from an outside source.

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Example: When an atom absorbs energy from a photon, its electron jumps from a lower-energy 'ground state' to a higher-energy, unstable 'excited state'.

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Quantum Number Noun

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[kwon-tuhm nuhm-ber]

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Quantum Number

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A number assigned to an electron in an atom that describes its properties, such as its energy and orbital characteristics.

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Example: The principal quantum number (n) describes an electron's main energy level or shell, with higher numbers representing shells farther from the atom's nucleus.

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Bohr's Model Noun

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[borz mod-l]

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Bohr's Model

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A quantum model for the hydrogen atom where electrons move around the nucleus in specific, allowed circular orbits or energy levels.

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Example: This diagram shows the Bohr model of an atom, with a central nucleus (protons and neutrons) and electrons orbiting in fixed, circular paths called electron shells.

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Lyman Series Noun

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[ly-muhn seer-eez]

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Lyman Series

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A series of spectral lines in the ultraviolet region that result from electron transitions down to the n=1 energy level.

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Example: This diagram shows that the Lyman series occurs when an electron in a hydrogen atom drops from any higher energy level (n>1) to the lowest energy level (n=1).

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Balmer Series Noun

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[bahl-mer seer-eez]

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Balmer Series

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A series of spectral lines in the visible light region that result from electron transitions down to the n=2 energy level.

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Example: This image shows the Balmer series, the unique pattern of colored light lines that a hydrogen atom (H) emits in the visible spectrum.

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Paschen Series Noun

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[pash-en seer-eez]

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Paschen Series

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A series of spectral lines in the infrared region that result from electron transitions down to the n=3 energy level.

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Example: This diagram shows the Paschen series, where an electron in a hydrogen atom falls from a higher energy level to the third energy level (n=3).

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Quantum Mechanical Model Noun

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[kwon-tuhm me-kan-i-kuhl mod-l]

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Quantum Mechanical Model

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The modern atomic model that treats electrons as waves and describes their location in terms of probability, not a fixed path.

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Example: This model shows a dense nucleus of protons and neutrons surrounded by a 'cloud' representing the probable locations of electrons, not fixed paths.

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de Broglie Equation Noun

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[de broy ee-kway-zhuhn]

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de Broglie Equation

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An equation relating a particle's wavelength to its mass and velocity, predicting that all moving particles have wave characteristics.

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Example: This image shows that something can be viewed as a wave or as a particle, illustrating the concept of wave-particle duality for matter like electrons.