Transcript Electron Configuration

Where is the Electron
Located?
WHAT IS ENERGY?
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ABILITY TO DO WORK
MEASURED IN JOULES (J)
WORK: TO USE A FORCE TO MOVE AN
OBJECT A DISTANCE
FXd
KINETIC: ENERGY DUE TO MOTION
POTENTIAL: ENERGY DUE TO POSITION
WHAT ARE THE DIFFERENT
FORMS OF ENERGY?
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Law Of Conservation of Energy (also known
as the First Law of Thermodynamics): Energy
cannot be created or destroyed it merely
changes form
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HEAT (THERMAL)
ELECTROMAGNETIC
CHEMICAL
NUCLEAR
MECHANICAL
SOUND
LIGHT (RADIANT)
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THE DUALITY OF LIGHT
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LIGHT IS A VIBRATION
(WAVE) IN ELECTRIC AND
MAGNETIC FIELDS THAT
CAN TRAVEL ACROSS
SPACE AS A PHOTON
(PACKET OF ENERGY).
IT IS PART OF THE
ELECTROMAGNETIC
SPECTRUM.
LIGHT CAN BE
REFLECTED, REFRACTED
AND DIFFRACTED
WAVE PROPERTIES
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WAVELENGTH (λ): DISTANCE BETWEEN TWO
IDENTICAL POINTS ON A WAVE (METERS, m)
FREQUENCY (ƒ): NUMBER OF WAVES THAT PASS A
FIXED POINT IN A SECOND (HERTZ, Hz)
SPEED OF LIGHT:
c = ƒλ
(3.00 X 108 m/s)
Waves
Albert Einstein
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Suggested that electromagnetic radiation can be
viewed as a stream of particles called photons
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PHOTOELECTRIC EFFECT: Ejection of electrons
from the surface of a metal or other material when
high energy/frequency light shines on
E =hƒ
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E = Energy
H = Planck’s Constant(6.63 X 1034 J/s)
f = Frequency
Albert Einstein
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Developed the equation E = mc2
Energy has mass
We can calculate the mass of a photon
Arthur Compton
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Collided X-rays with electrons
Showed that photons do exhibit the
mass from Einstein’s equation
Nature of Matter
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Max Planck – German physicist
Experimented with energy
Energy can be lost or gained only in
whole-number multiples
Energy is “quantized”
Summary
Energy is quantized
 Electromagnetic radiation exhibits wave-like and
particle-like behavior
 Large pieces of matter mostly exhibit particle-like
properties
 Tiny pieces, like photons, exhibit mostly wave-like
 Intermediate, like electrons, exhibit both
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The Bohr Model
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Developed a quantum model for hydrogen
Electrons moved in circular orbits around
the nucleus
Equation that can be used to calculate the
change in energy when an electron
changes orbits:
E = -2.178 X 10-18J (Z2/n2)
n = an integer
Z = nuclear charge
BOHR’S ATOMIC THEORY
HOW CAN A LINE SPECTRA
IDENTIFYAN ELEMENT?
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LINE SPECTRUM: Shows only specific
wavelengths of light (EM spectra)
What are uses of line
Spectra in technology?
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The Bohr Model
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Ground state – lowest possible energy state for an
electron
Suppose an electron in level n = 6 of an excited
hydrogen atom falls back to level n = 1. Calculate
the change in energy when this happens.
ΔΕ = energy of final state – energy of initial state
What is the wavelength of the emitted photon?
E = -2.178 X 10-18J (Z2/n2)
E =hƒ
c = ƒλ (c = 3.00 X 108 m/s)
The Quantum Mechanical Model
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Bohr’s equation only worked for hydrogen
Heisenberg, de Broglie, and Schrodinger
developed the theory behind our current model
Schrodinger came up with a mathematical
equation to describe the location of the electron
A specific wave function = an orbital
Led to the Heisenberg uncertainty principle and
the exact speed of light (c)
The Quantum Model of the Atom
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Heisenberg
uncertainty principle:
It is impossible to
determine both the
position and velocity
of an electron or any
other particle
What is the Address of the
Electron?
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Principle Quantum Number (n): Indicates the
energy level occupied by an electron.
Angular Momentum (l): Indicates the shape of
the orbital (s,p,d,f,g)
Atomic Numbers and Quantum
Numbers
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Magnetic Quantum Number (m): Indicates the
orientation of an orbital around the nucleus.
Spin Quantum Number (↓↑): Indicates which
way the electron is spinning
Quantum Numbers
Symbol
What It Means
Acceptable Values
n
Main energy level 1, 2, 3, 4, etc.
l
Orbital shape
ml
Space orientation -l…0…+l
ms
Electron spin
0, 1, 2,…n-1
+1/2 and -1/2
What are the Rules Governing
Electron Configuration?
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Aufbau Principle: An electron occupies
the lowest energy orbital available
Pauli Exclusion Principle: Only two
electrons per orbital and they must spin
in opposite directions
Hund’s Rule: Each orbital of equal
energy must have one electron before a
second electron is added
Let’s Fill Up The Orbitals!
Summary of Orbitals
Principle
Sublevels
Quantum #
1
s
Number of Number of
Orbitals
Electrons
1
2
2
s, p
3
8
3
s, p, d
5
18
4
s, p, d, f
7
32
Exceptions to Aufbau