Chapter 5
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Electromagnetic waves
According to the wave model, light consists of _________________ _______________.
Classical mechanics
Adequately describes the motions of bodies much larger than atoms
Pauli exclusion principal
An atomic orbital may describe at most two electrons
Yes
Can the range of energy levels of a principle energy level overlap the energy levels of another?
No
Can two elements have the same emissions spectrum?
Quantum mechanical model
Comes from the mathmatical solutions to the Schrodinger equations
Sunlight
Consists of light with a continuous range of wave lengths and frequencies
Rutherford's atomic model
Could not explain the chemical properties of elements
Each complete wave cycle starts at zero, increases to its highest value, passes through zero to reach its lowest value and returns to zero to the crest
Describe the property of a wave
Probability
Describes how likely it is to find the electron in a particular location
Quantum mechanics
Describes the motions of subatomic particles and atoms as waves
Quantum mechanical model
Determines the allowed energies an electron can have and how likely it is to find the electron in varius locations around the nucleus
Earnest Rutherford
Discovered the atomic nucleus and used existing ideas about the atom and proposed an atomic model in which the electrons move around the nucleus
Waves
Does light consist of waves or particles?
No
Does the heist berg uncertainty principle apply to large scale items?
1911
Earnest Rutherford finds small positively charged nucleus
Hund's rule
Electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible
Aufbau principle
Electrons occupy the orbitals of lowest energy first
1926
Erwin schrodinger developed mathematical equation to discribe the motion of electrons in atoms (leads to electron cloud model)
copper- 4s1 instead of 4s2 at the end chromium- 4s1 instead of 4s2 at the end
Exceptions to electron configuration
1904
Hantaro Nagaoka suggestion of nucleus and structured electron path
E=hv
How to find energy using planks constant and frequency
Fixed energy
In Bohr's model, what did each possible electron orbit have?
Lowest possible energy level
In most natural phenomena, change proceeds to the ___________________.
Electromagnetic waves
Includes radio waves, radar, microwaves, infrared, ultraviolet, x-rays, gamma rays
up ad down arrows
Indicates an electron and its direction of spin; used to write paired electrons
Paschen series
Infrared
Nucleus and electrons
Interact with each other to make the most stable atomic arrangement
No
Is the amount of energy an electron gains or loses in an atom always the same?
1897
J.J. Thomson's plum pudding atom
1932
Jams Chadwick confirms the existence of neutrons
1803
John Daltons atom
Photons
Light quanta
1923
Louis de Broglie proposed electrons have wavelike properties
1913
Niels Bohr electron orbit model
6.626x10 -34 js
Planks constant
Wavelength
Represented by lambda; the distance between the crests
Frequency
Represented by the v; the number of wave cycles to pass a given point per unit of time; labled Hz or s-1
c= 2.998 x 10^8 m/s
Speed of light
Heisenburg uncertainty principle
States that it is impossible to know exactly both the velocityand the position of a particle at the same time
Propeller blade
The QM model description of how the electron moves around the nucleus is simular to a __________________ ________________.
A quantum
The amount of energy required to move an electron from one energy level to another (up of down)
frequency
The color emitted for each frequency found in sunlight depends on its....
Quantized
The energy of an electron is said to be __________________.
Atomic emissions spectrum
The frequencies of light emitted by an element separate into discrete lines
Closer
The higher the energy level the ______________ the orbitals are to one another
Bohrs model
The ideas and theories of quantum mechanics originates from the ideas found in which atomic model?
the energy change of the electron
The light emitted by an electron moving from a higher to a lower energy level has a frequency directly proportional to ...
Farther
The lower the energy level the ______________ the orbitals are from one another
Of equal energy
The orbitals for any sub level of a principle energy level are always ...
Ground state
The principal quantum number is 1
Inversely proportional
The wavelength and frequency of light are __________ to each other
Electron configurations
The ways in which electrons are arranged in various orbitals around the nuclei of atoms
1. Aufbau principle 2. Pauli exlusion Principle 3. Hund's rule
Three rules of electron configuration
Opposite
To occupy the same orbital, electrons must have ______________ spins.
Isaac Newton (1642-1727)
Tried to explain what was known about the behavior of light and proposed that light consisted of waves
a photon
Type of energy that forms light when the electron drops back to a ground state
Lyman series
Ultraviolet
Quantum leap
Used to describe the electrons abrupt jump from one energy level to the next
Balmer Series
Visible
Amplitude
Waves height from zero to the crest
1. like the Bohr model, the QM model restricts the energy of electrons to certain values 2. Unlike the Bohr model, the QM model does not involve the exact path the electron takes around the nucleus
What are some similarities and differences between the Bohr model and quantum mechanical model
1. The Rutherford planetary model 2. The Bohr model
What are the two atomic models that are based on describing paths of moving electrons
Atomic emissions spectra
What can be used to identify an element?
The rungs of a ladder - The lowest rung represents the lowest energy levels - The highest rung represetns the highest energy levels - Sometimes the rungs/ orbits are not evenly spaced and get smaller as energy increases. In these cases, it requires less energy to move them the closer the orbits are
What can the energy levels of an atom be compared to?
Subtle electron-electron interactions in orbitals with very simular energies
What causes exceptions in the aufbau principle?
Red
What color has the longest wavelength and lowest frequency?
How the energy of an atom changes when it absorbs or emits light
What did Bohr add to Rutherford's atomic model to improve it?
Why the emission spectrum of hydrogen consists of specific frequencies of light and it predicted the specific values of these frequencies
What did Bohr model explain concerning the hydrogen atom?
An electron is found only in specific circular paths, or orbits, around the nuclues
What did Bohr propose about electrons reguarding rutherfords model?
Why objects change color when heated
What does Rutherford's model fail to explain (specifically)
One exact frequency of light emitted by the atom
What does each discrete line in an emission spectrum corespond to?
It energizes the electrons of the atoms of the gas and causes them to emit light
What does passing an electric current through a gas in a neon tube do?
Electrons move into a higher energy level
What happens when atoms absorb energy?
The different frequencies separate in to a spectrum of colors
What happens when sunlight is passed through a prism?
They loose energy by emitting light
What happens when the electrons move back energy levels?
It still failed in many ways to explain the energies absorbed and emitted by atoms with more than one electron
What was wrong with the Bohr model of the atom?
Sometimes filled energy sub levels are more stable than partially filled sublevels
Why are some of the chromium and copper sublevels only half filled?
s
lowest sub level
