Quantum Mechanics & Electron Configuration
-
Upload
uriah-hale -
Category
Documents
-
view
45 -
download
2
description
Transcript of Quantum Mechanics & Electron Configuration
![Page 1: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/1.jpg)
Quantum Mechanics & Electron Configuration
Chapter 5: Electrons in Atoms
![Page 2: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/2.jpg)
Part 1: Models of the Atom
1897: Thompson Model (Plum Pudding)
1911: Rutherford Model – Small, dense, + charged nucleusElectrons orbit around
1913: Bohr Model
1926: Quantum Mechanical Model – Erwin Schrodinger & his math equations
![Page 3: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/3.jpg)
Bohr Model (aka the versions you’ve learned before)
Electrons move around the nucleus in fixed spherical orbits with fixed energies Fixed energies = orbits / energy levels
Aka rungs of a ladder
Electrons can go to a higher or lower energy level Either gain or lose energy to move levels
Electrons CANNOT be between levels
![Page 4: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/4.jpg)
Atomic Emission Spectra** When atoms absorb energy (i.e. electric current), they move to a higher energy level …
… these electrons emit light when they return back to a lower energy level
Emission spectra is unique for each element- The light emitted consists of only a mixture to specific
frequencies…
If you pass the light through a slit and then a prism, you can separate the resulting light into its frequencies (aka colors)
Barium
![Page 5: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/5.jpg)
Light
Has properties of both: a Particle ( ____________) a Wave
Light Waves:Amplitude: crest of the wave (height from 0)Wavelength: distance between crests (λ)Frequency: # of waves per unit time (ν)
Units: Hertz (Hz) aka s-1
![Page 6: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/6.jpg)
![Page 7: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/7.jpg)
Math Time!!!
c = λνC = speed of light (constant) = 2.998 x 108 m/s
λ = Wavelength (m)
ν = Frequency (Hz or s-1)
![Page 8: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/8.jpg)
![Page 9: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/9.jpg)
More Math… The energy (E) of a photon is directly
proportional to its frequency. Higher freq = More EnergyLower Freq = Less Energy
E = h x v
E = energy (joules – J)H = Plank’s constant = 6.626E-34 J/sv = Frequency (Hz or s-1)
![Page 10: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/10.jpg)
Example:
What is the energy of a quantum of light with a frequency of 7.39 x 1014 Hz?
![Page 11: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/11.jpg)
Think about this… E = h x v c = λν
What would you do if you were asked to solve for the frequency of light if you are given a wavelength of 700nm?
What would you do if you were asked to find the energy of light if you are given a wavelength of 480nm?
![Page 12: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/12.jpg)
Emission Spectra LabLook at the gas tubes and follow directions provided.
![Page 13: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/13.jpg)
Continuous Spectrum v. Line Spectrum What did you observe in the Emission
Lab?
![Page 14: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/14.jpg)
Light has Wave-Particle Duality (& so do electrons)
Particle & Wave-like Nature Depends on experiment / what we try to
observe
Throws a wrench in Bohr Model… New method of describing the motion of
subatomic particles= foundation of quantum mechanics = movement/organization of subatomic particles
![Page 15: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/15.jpg)
The Quantum Mechanical Model
This is what we use today
Describes: LOCATION & ENERGY of electrons
Electrons do not have a direct orbit around nucleus Based on probability Electron clouds
Electrons do have energy levels
![Page 16: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/16.jpg)
Hog Hilton Sample Problem Book 15 hogs into their rooms
6th floor ____ ____ ____ _____ _____6th floor ______5th floor ______ ______ ______4th floor ______3rd floor ______ ______ ______2nd floor ______1st floor ______
![Page 17: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/17.jpg)
Hog Hilton Sample ProblemPlace 15 electrons into their spaces
3d_____ _____ _____ _____ ____4s _____3p ______ ______ ______3s ______2p ______ ______ ______2s ______1s ______
![Page 18: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/18.jpg)
But…all of these electrons are not organized into hotel rooms, but ATOMIC ORBITALS
![Page 19: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/19.jpg)
So, what exactly is an ATOMIC ORBITAL?
Atomic Orbital = region of space in which there is a high probability of finding an electron
They come in different SHAPES, SIZES & ENERGY LEVELS!!
These are described by Quantum Numbers…
![Page 20: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/20.jpg)
Part 2Quantum Numbers
Get ready…here we go…
![Page 21: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/21.jpg)
Quantum Numbers
Used to describe the location of electrons
Electrons in an atom CANNOT have the same quantum numbers
Unique for each electron Like an address
![Page 22: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/22.jpg)
Principle Quantum Number (think…Energy Level)
n
Allowable values = 1, 2, 3 … n (positive, integer values)
Describes energy level
Position of the electron w/ respect to nucleus As n increases = further from nucleus
![Page 23: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/23.jpg)
Angular Momentum Quantum Number (Azimuthal Quantum Number)(think…energy sublevel)Pay attention…this is where it starts to get complicated
l
Allowed values: 0, 1, 2, … (n-1)
Describes the sublevel SHAPE of the orbital
SHAPES: l = 0 = s orbital = spherical cloud l = 1 = p orbital = dumbbell cloud l = 2 = d orbital = clover cloud l = 3 = f orbital = … too complicated
![Page 24: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/24.jpg)
Example If I had a principal quantum number of
2, what are my possible angular momentum quantum numbers?
n = 2
l =
![Page 25: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/25.jpg)
Angular Momentum Quantum Number: Orbital Shapes
![Page 26: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/26.jpg)
Magnetic Quantum Number (ml) Determines spatial orientation (x, y, z, plane)
Possible Values: - l to + l Examples: if it is a d orbital
d orbital:l = ml =
![Page 27: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/27.jpg)
Example: p-orbitaln = 2l = ml =
This means, there are _______ p-orbitals and that they are in three directions (x, y, z axes):
![Page 28: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/28.jpg)
What orbital corresponds to :n = 2l = 1ml = 0
Energy level =Sublevel = _____ - orbitalOrientation:Orbital:
![Page 29: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/29.jpg)
Number of orbitals within an energy level: n2
Examples: How many orbitals are in energy level 2?n = l = ml =
Orbitals =
Each orbital holds 2 electrons:So, how many electrons can energy level 2 hold?
# Electrons = 2n2
![Page 30: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/30.jpg)
Spin Quantum Number
ms
Describes the direction of the electrons spin within an orbital (remember, each orbital only holds 2 electrons)
Possible Values: ½ or -½ (spin up, spin down)
Think back to hogs…
![Page 31: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/31.jpg)
Ahhh…it’s too much information…HELP!!!
Solution: STUDY and PRACTICE!!!
Quantum # Symbol Possible Values Description
Principle Quantum Number
n 1, 2, 3, etc Energy level
Angular Momentum
Quantum Number
l 0 … n-1 Sublevel & shape
Magnetic Quantum Number
ml -l … +l Spatial Orientation of orbital (x,y,z)
Spin Quantum Number
ms +½ or -½ Direction of Spin
![Page 32: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/32.jpg)
Examples
1. n = 3 (what are the possible quantum numbers?)
2. What orbital corresponds to n = 4 & l = 2?
![Page 33: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/33.jpg)
What orbital corresponds to n = 4 , l = 1, ml = -1
Energy Level = Sublevel = Orbital orientation = Orbital =
![Page 34: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/34.jpg)
Re-iterate:Orbital How Many Types of
Orbitals (orientations)
How Many Electrons in Shape
s 1
p 3
d 5
f 7
![Page 35: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/35.jpg)
Principle Quantum Number
(n)
Angular Momentum Quantum Number
(sublevels)(l)
Shapes of Sublevels
# electrons (2n2)
1
2
3
4
5
6
7
![Page 36: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/36.jpg)
Principle Quantum Number
(n)
Angular Momentum
Quantum Number (sublevels)
(l)
Shapes of Sublevels
# electrons (2n2)
1 0 s 2
2 0, 1 s p 8
3 0, 1, 2 s p d 18
4 0, 1, 2, 3 s p d f 32
5 0, 1, 2, 3, 4 s p d f (g) 50
6 0, 1, 2, 3, 4, 5 s p d f (g h) 72
7 0, 1, 2, 3, 4, 5, 6 s p d f (g h i) 98
![Page 37: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/37.jpg)
STOPDo You Have Any Questions?
![Page 38: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/38.jpg)
PART 3 Rules of Electron Configuration
![Page 39: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/39.jpg)
Aufbau Principle
Electrons enter orbitals of lowest energy first
Orbitals within a sublevel have equal energy(3px, 3py, 3pz)
Exceptions: Cr , Cu
Which hog rules is this?
![Page 40: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/40.jpg)
Pauli Exclusion Principle An atomic orbital may only hold two
electrons
Electrons must have opposite spin
Clockwise or counterclockwise spin Denoted with arrows Prevents two electrons from having same quantum
numbers
Which hog rule is this?
![Page 41: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/41.jpg)
Hund’s Rule
Every orbital of the same energy is singly occupied before any orbital is doubly occupied
Electrons have the same spin
Second electrons added have opposite spins
Which hog rule is this?
![Page 42: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/42.jpg)
PART 4
Writing Electron Configurations
![Page 43: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/43.jpg)
Electron Configuration Diagonal Rule Starting with the top
arrow, follow the arrows one by one in the direction they point, listing the sublevels as you pass through them.
Stop when you get to the sublevel you need.
![Page 44: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/44.jpg)
Electron Orbital Diagram3d ___ ___ ___ ___ ___4s ___3p ___ ___ ___3s ___2p ___ ___ ___2s ___1s ___
![Page 45: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/45.jpg)
Example: Fill Orbitals w/ 7 electrons3d ___ ___ ___ ___ ___4s ___3p ___ ___ ___3s ___2p ___ ___ ___2s ___1s ___
![Page 46: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/46.jpg)
Review:1. How many electrons fill an s orbital?
2. How many electrons fill a p orbital ?(remember subshells…)
3. How many electrons fill a d orbital?
4. How many electrons fill an f orbital?
![Page 47: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/47.jpg)
Example: Cl3d ___ ___ ___ ___ ___4s ___3p ___ ___ ___3s ___2p ___ ___ ___2s ___1s ___
Give the final E.C:
![Page 48: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/48.jpg)
With a partner:Examples: Give the E.C
H He Li Be B C N F
![Page 49: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/49.jpg)
No more…Make it stop!@!!!! Write the electron configuration for Barium:
Ahhhhhhhhhh!!! Too many electrons!!
But wait…there’s a shortcut…
Noble gas / shorthand configuration: Find the nearest noble gas that came before the
element you are interested in Write the symbol of that noble gas in [brackets] Write the configuration as normal from there…
![Page 50: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/50.jpg)
Examples: Sb
![Page 51: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/51.jpg)
Stop & Practice E.C. Worksheet
![Page 52: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/52.jpg)
All Together Now… Mendeleev didn’t know quantum numbers
BUT…our periodic table is related to HOW electrons fill the levels in the different shells
Blocks s block
Groups 1 & 2 p Block
Groups 3 – 8 d block
Transition Elements f Block
Rare earth metals
![Page 53: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/53.jpg)
It ends w/…
![Page 54: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/54.jpg)
Another Example: Ba (shorthand)
![Page 55: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/55.jpg)
Stop & Practice
Patterns in Electron Configuration Worksheet
![Page 56: Quantum Mechanics & Electron Configuration](https://reader035.fdocuments.us/reader035/viewer/2022062217/568130b6550346895d96d2c2/html5/thumbnails/56.jpg)
ColumnsElements have similar properties
Why?Similar ground state electron configurations
ExamplesNoble gases
Complete sublevel Favorable - do not react
Halogens One electron short of completely filled sublevel
Readily react with elements who have a single electron