Emission Spectra and Atomic Models
Emission of Energy by Atoms
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Ground state: An atom with its electrons in the _______________ possible energy levels (closer
to the nucleus)
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Excited state: Electrons that _______________ energy and occupy _______________ energy
levels (further from the nucleus)
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When heated, an electron can absorb energy, become ____________________, and move to a
higher energy level
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When it loses that energy and falls back to the ____________________ state, the electron emits
the same amount of energy as a photon
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The energy of the photon _______________ as the electron falls from the excited state back to
the ground state corresponds to a specific frequency of light
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If the frequency is within the ____________________ spectrum, we can see it
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The ___________________ we see is determined by the frequency of the photon
Emission Spectra of Elements
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Spectrum- a band of colors, produced by separation of the components of light by their different
degrees of refraction according to wavelength
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When _______________are connected to a voltage source and heated, they glow and emit light
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The light that is emitted by the hot gas can be shined through a prism and split into __________
wavelengths which we see as lines against a dark background
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The _______________ in the emission spectrum represent the energy released by the photons
as the electrons fall from the excited state back to the ground state.
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Since light is quantized, the energy levels within the electron cloud of that element correspond
to specific photon wavelengths.
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Because every element has a ____________________ “light signature”, an emission spectrum
can be used to identify the element
Emission Spectrum of Hydrogen
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The emission spectrum of hydrogen has _______________ spectral lines
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The emission spectrum of hydrogen, in conjunction with the photoelectric effect, provided the
evidence Bohr needed to develop his model of the atom
Bohr’s Model of the Atom
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Bohr’s model of the atom involved electrons moving around the nucleus, in fixed, circular orbits,
like planets around the sun.
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Bohr said that the energy of electrons is quantized; therefore, electrons can occupy only certain
orbits or energy levels.
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Quantum- amount of energy required to _______________ an electron from one energy level to
another energy level
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Think about a ladder to understand the concept of quantized electron energy levels:
➢ Lowest rung is lowest energy level (n =1)
➢ You can move from rung to rung, but you cannot step between rungs.
➢ Similarly, an electron can move from energy level to energy level, but it cannot exist
between levels
➢ You must have correct amount of energy to move from rung to rung, just as an
electron must have correct amount of energy to move from level to level
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The Bohr Model is important because it showed us that _____________________________
exist within the atom and that electrons can change energy levels when they absorb (gain) or
emit (lose) energy
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The _____________________ with Bohr’s model is that it worked only for hydrogen and not
atoms with more than one electron.
Quantum Mechanical Model
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The quantum mechanical, or _______________________________, model is what we use today
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Electrons move unpredictably within ____________________ inside the electron cloud
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Orbital-a representation, or ____________________ map, of the space occupied by an electron
within an atom