Modern atomic theory History, Concepts, Electron Configurations
History
•  Max
Planck •  Theorized
that behavior of light can be explained by assuming
that energy is gained or released in discrete packets (“quanta”)
•  Planck’s
Constant (6.63 x 10-34 J • s)
history
•  Wave-Particle
•  All
duality
matter can exhibit wave and particle properties
History
•  de
Broglie •  Proposed
that wave properties are observed for particles with
very small masses
•  “My essential idea was to extend to all particles the coexistence of waves and particles
discovered by Einstein in 1905 in the case of light and photons.”"
History
•  Schrodinger
•  Used
math equations to determine the probable location of
an electron in an atom
History
•  Heisenberg
•  The
more an observer knows of an electron’s position, the
less the observer knows of the electron’s momentum (mv),
and vice versa
History
•  Pauli
principle: no two electrons can share the same four
quantum numbers
•  Exclusion
•  Developed
the idea of electron “spin”
Quantum numbers
•  Principal
•  Describes
Quantum Number
the “size” of the orbital - how far away from
nucleus
•  The
farther away the orbital, the larger the Principal Quantum
Number, the higher the energy
Quantum Numbers
•  2nd
Quantum Number (angular quantum number)
•  Describes
•  s,
p, d, f
shape of orbital Quantum Numbers
•  3rd
Quantum Number
•  Orientation
of Orbital •  E.g. Px, Py, Pz
Quantum number
•  4th
Quantum Number
•  “Spin”
•  Two
number
electrons in same orbital must have opposite spin
Electron configurations
•  Ca
•  20
e-
•  1s2
2s2 2p6 3s2 3p6 4s2
Electron configurations
•  Pu
•  94
(Plutonium)
e-
2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6
7s2 5f6
•  1s2
•  [Rn]
7s2 5f6