Section 7.2- Electrons and the Structure of the Atom Flashcards
a more precise instrument that can be used in the laboratory to separate the colors even further and study them in more detail
spectrometer
a spectrum containing only certain colors (wavelengths) is a
line spectrum
a spectrum containing the complete array of colors, is a
continuous spectrum
allowed scientists to study elements in an entirely new way
discovery of line spectra
virtual fingerprint
line spectrum
presented the atom as a miniature solar system with electrons orbiting like planets
Rutherford’s planetary model
the problem withe Rutherford’s planetary model
the electron would spiral closer to the nucleus as it gradually lost energy, eventually colliding with the nucleus and destroying the atom
proposed a new model of atomic structure that explains both why the lines in the hydrogen spectrum are mathematically related and why the atom does not self-destruct
Niels Bohr
using aspects of Planck’s quantum theory, Bohr explained that the electron in the hydrogen atom can move about the nucleus only in specific orbits called
energy levels
only certain orbits are allowed; the energy of the allowed orbits is _________________
quantized (restricted to certain values)
equation for energy quantized
E = -J (a constant) / nsquared (quantum number)
the lowest energy state
ground state
the ground state of the hydrogen atom is the state where
n = 1
all other higher-energy states are said to be
excited states
the ______________ energy state possible is the most stable
lowest
gives us the energy of the photon emitted in a transition
E2 - E1 = hf
both ______________ and _________________ are quantized.
absorptions
emissions
problem with Bohr’s model
it fails to account for the spectra of atoms containing more than one electron
a French physicist who proposed that since radiation has properties of particles, then particles in motion should have properties of waves
Louis de Broglie
the waves de Broglie proposed
matter waves
matter waves cannot move at the
speed of light
the equations for the matter waves wavelength
lambda = h (Planck’s constant) / mv
the electron can be shown to behave as a ____________ as well as a _____________
wave and particle
applies to all waves and all particles, though for macroscopic objects the wave properties are too small to measure and are ignored
wave-particle duality
combined the Bohr model with de Broglie’s hypothesis to propose the wave- mechanical model
Erwin Schrodinger
according to this model of the atom, an electron in an atom behaves as a three-dimensional matter wave containing an integral number of wavelengths in an orbit
Schrodinger’s wave-mechanical model
a three-dimensional matter wave containing an integral number of wavelengths in an orbit is known as a
standing wave
stated the uncertainty principle
Werner Heisenberg
states that it is impossible to simultaneously determine the momentum (mass times velocity) and the position of an electron with precision; either momentum or position may be precisely measured, but not both
uncertainty principle
in Born’s interpretation, electrons are treated as pointlike particles rather than waves but are not regarded as having definite orbits through space; instead, they are said to move in regions called
orbitals
a region of space in which there is a high probability of finding the electron
orbital
a definite path in space
orbit
Born’s interpretation of the wave-mechanical model is sometimes called the
electron-cloud model
Born’s interpretation is simply another way of looking at ____________________
Schrodinger’s equations
