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Emission Spectra and Atomic Models
Emission of Energy by Atoms
Ground state: An atom with its electrons in the _______________ possible energy levels (closer
to the nucleus)
Excited state: Electrons that _______________ energy and occupy _______________ energy
levels (further from the nucleus)
When heated, an electron can absorb energy, become ____________________, and move to a
higher energy level
When it loses that energy and falls back to the ____________________ state, the electron emits
the same amount of energy as a photon
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
If the frequency is within the ____________________ spectrum, we can see it
The ___________________ we see is determined by the frequency of the photon
Emission Spectra of Elements
Spectrum- a band of colors, produced by separation of the components of light by their different
degrees of refraction according to wavelength
When _______________are connected to a voltage source and heated, they glow and emit light
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
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.
Since light is quantized, the energy levels within the electron cloud of that element correspond
to specific photon wavelengths.
Because every element has a ____________________ “light signature”, an emission spectrum
can be used to identify the element
Emission Spectrum of Hydrogen
The emission spectrum of hydrogen has _______________ spectral lines
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
Bohr’s model of the atom involved electrons moving around the nucleus, in fixed, circular orbits,
like planets around the sun.
Bohr said that the energy of electrons is quantized; therefore, electrons can occupy only certain
orbits or energy levels.
Quantum- amount of energy required to _______________ an electron from one energy level to
another energy level
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
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
The _____________________ with Bohr’s model is that it worked only for hydrogen and not
atoms with more than one electron.
Quantum Mechanical Model
The quantum mechanical, or _______________________________, model is what we use today
Electrons move unpredictably within ____________________ inside the electron cloud
Orbital-a representation, or ____________________ map, of the space occupied by an electron
within an atom