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Chemistry Chapter 5 Chemistry Chapter 5 Electrons in Atoms Electrons in Atoms The 1998 Nobel Prize in P hysics was awarded "for the discovery of a new form of quantum fluid with fractionally charged excitations." At the left is a computer graphic of this kind of state.

Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

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Page 1: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Chemistry Chapter 5Chemistry Chapter 5Electrons in AtomsElectrons in Atoms

The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally charged excitations." At the left is a computer graphic of this kind of state.

Page 2: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Electrons in AtomsElectrons in Atoms

•Thomson – plum pudding•Disproven

•Rutherford – •Bohr

Page 3: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

The Puzzle of the AtomThe Puzzle of the Atom   Protons and electrons are attracted to each

other because of opposite charges

  Electrically charged particles moving in a curved path give off energy

  Despite these facts, atoms don’t collapse

Page 4: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

So why didn’t the atom collapse??

Why doesn’t the electron lose energy as it orbits???

Page 5: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

• Hold onto your spectral tubes!!

• The answer actually has to do with light and other electromagnetic radiation.

Page 6: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Wave-Particle DualityWave-Particle DualityJJ Thomson won the Nobel prize for describing the electron as a particle.

His son, George Thomson won the Nobel prize for describing the wave-like nature of the electron.

The electron

is a particle!

The electron is an energy

wave!

So there was a difference in opinion between a father and son. Has this ever happened to you?

Page 7: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Electrons have properties of

Waves and Particles

So father and son BOTH right!!

Page 8: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Confused??? You’ve Got Confused??? You’ve Got Company!Company!

“No familiar conceptions can be woven around the

electron; something unknown is doing we

don’t know what.”

Physicist Sir Arthur Eddington

The Nature of the Physical World

1934So even the smart dudes were baffled

Page 9: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

The Wave-like ElectronThe Wave-like Electron

Louis deBroglie

The electron propagates through space as an energy

wave. To understand the atom, one must

understand the behavior of

electromagnetic waves.Ok …. so in order to argue with my dad I need to understand light?

Page 10: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Maybe I should learn about light

Page 11: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

c = C = speed of light, a constant (3.00 x 108 m/s)

= frequency, in units of hertz (hz, sec-1)

= wavelength, in meters

Electromagnetic radiation Electromagnetic radiation propagates through space as a wave propagates through space as a wave moving at the speed of light.moving at the speed of light.

Page 12: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Types of electromagnetic radiation:Types of electromagnetic radiation:

Page 13: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

E = h EE = Energy, in units of Joules (kg·m= Energy, in units of Joules (kg·m22/s/s22))

hh = Planck’s constant (6.626 x 10-34 J·s)= Planck’s constant (6.626 x 10-34 J·s)

= frequency, in units of hertz (hz, sec= frequency, in units of hertz (hz, sec-1-1))

The energy (The energy (E E ) of electromagnetic ) of electromagnetic radiation is directly proportional to radiation is directly proportional to the frequency (the frequency () of the radiation.) of the radiation.

Page 14: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Long Wavelength

= Low Frequency

= Low ENERGY

Short Wavelength

= High Frequency

= High ENERGY

Wavelength TableWavelength Table

Page 15: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

…produces all of the colors in a continuous spectrum

Spectroscopic analysis of the visible of the visible spectrum…spectrum…

Page 16: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

…produces a “bright line” spectrum

Spectroscopic analysis of the Spectroscopic analysis of the hydrogen spectrum…hydrogen spectrum…

Page 17: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

This produces bands of light with definite wavelengths.

Electron Electron transitionstransitionsinvolve jumps of involve jumps of definite amounts definite amounts ofofenergy.energy.

Page 18: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Spectral tubes, flame tests and fireworks…all colored by electrons changing energy levels.

Page 19: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

The Bohr Model of the AtomThe Bohr Model of the Atom

Neils Bohr

I pictured electrons orbiting the nucleus much like planets orbiting the sun.But I was wrong! They’re more like bees around a hive.

WRONG!!!

Page 20: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

  Standing waves do not propagate through space   Standing waves are fixed at both ends  

Only certain sized orbits can contain whole numbers of half wave lengths.

The electron as a standing The electron as a standing wave:wave:

Page 21: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Quantum NumbersQuantum Numbers

Each electron in an atom has a unique set of 4 quantum numbers which describe it.

Principal quantum number (n) Angular momentum quantum number (l) Magnetic quantum number (m) Spin quantum number

Page 22: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Pauli Exclusion PrinciplePauli Exclusion Principle

No two electrons in an atom can have the same four quantum numbers.

Wolfgang Pauli

Page 23: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Principal Quantum NumberPrincipal Quantum NumberGenerally symbolized by n, it denotes the shell (energy level) in which the electron is located.

Number of electrons that can fit in a shell:

2n2

Page 24: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Angular Momentum Angular Momentum Quantum NumberQuantum Number

The angular momentum quantum number,

generally symbolized by l, denotes the orbital (subshell) in which the electron is located.

Page 25: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Magnetic Quantum NumberMagnetic Quantum NumberThe magnetic quantum number, generally symbolized by m, denotes the orientation of the electron’s orbital with respect to the three axes in space.

Page 26: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Assigning the NumbersAssigning the Numbers The three quantum numbers (n, l, and m) are integers. The principal quantum number (n) cannot be zero. n must be 1, 2, 3, etc. The angular momentum quantum number (l) can be any integer between 0 and n - 1. For n = 3, l can be either 0, 1, or 2. The magnetic quantum number (m) can be any integer between -l and +l. For l = 2, m can be either -2, -1, 0, +1, or +2.

Page 27: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Principle, angular momentum, and magnetic quantum Principle, angular momentum, and magnetic quantum numbers: numbers: nn, , ll, and , and mmll

Page 28: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Spin Quantum NumberSpin Quantum NumberSpin quantum number denotes the behavior (direction of spin) of an electron within a magnetic field.

Possibilities for electron spin:

1

2

1

2

Page 29: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Orbital shapes are defined as the surface that contains 90% of the total electron probability.

An orbital is a region within an atom where thereAn orbital is a region within an atom where thereis a probability of finding an electron. This is a is a probability of finding an electron. This is a probability diagram for the s orbital in the probability diagram for the s orbital in the first first energy level…energy level…

Page 30: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Schrodinger Wave EquationSchrodinger Wave Equation

22

2 2

8dh EV

m dx

Equation for probabilityprobability of a single electron being found along a single axis (x-axis)Erwin Schrodinger

Page 31: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Heisenberg Uncertainty Heisenberg Uncertainty PrinciplePrinciple

You can find out where the electron is, but not where it is going.

OR…

You can find out where the electron is going, but not where it is!

“One cannot simultaneously determine both the position and momentum of an electron.”

Werner Heisenberg

Page 32: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Orbitals of the same shape (s, for instance) grow larger as n increases…

Nodes are regions of low probability within an orbital.

Sizes of Sizes of ss orbitals orbitals

Page 33: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Orbitals in outer energy levels DO penetrate into lower energy levels.

This is a probability Distribution for a 3s orbital.

What parts of the diagram correspond to “nodes” – regions of zero probability?

Penetration #1

Page 34: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Which of the orbital types in the 3rd energy level Does not seem to have a “node”?

WHY NOT?

Penetration #2

Page 35: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

The s orbital has a spherical shape centered around the origin of the three axes in space.

s orbital shape

Page 36: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

There are three dumbbell-shaped p orbitals in each energy level above n = 1, each assigned to its own axis (x, y and z) in space.

PP orbital shape orbital shape

Page 37: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Things get a bit more complicated with the five d orbitals that are found in the d sublevels beginning with n = 3. To remember the shapes, think of “double dumbells”

…and a “dumbell with a donut”!

d orbital shapes

Page 38: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Shape of f orbitalsShape of f orbitals

Page 39: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Orbital filling tableOrbital filling table

Page 40: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Electron configuration of the Electron configuration of the elements of the first three elements of the first three

seriesseries

Page 41: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Irregular confirmations of Cr and CuIrregular confirmations of Cr and Cu

Chromium steals a 4s electron to half fill its 3d sublevel

Copper steals a 4s electron to FILL its 3d sublevel

Page 42: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

We have colors because of the movement of electron!! Ahh ChemisTRY

Page 43: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Chemistry ChapterChemistry Chapter 55Atomic StructureAtomic Structure

Presented by Mr. Presented by Mr. MoleMole

You will learn about You will learn about him later…him later…

Page 44: Chemistry Chapter 5 Electrons in Atoms The 1998 Nobel Prize in Physics was awarded "for the discovery of a new form of quantum fluid with fractionally

Mole Day 6:02 October 23

• Poor mister mole….we never celebrate his day because it takes to long to light his 6.02 x 10 23 candles