Modern Theory of the Atom Quantum Mechanical Model Or Wave Mechanical Model Or Schrodingers Model.
Quantum Mechanical Model
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Transcript of Quantum Mechanical Model
Quantum Mechanical Model
Electron Configuration
Quantum Mechanical Model
• Quantum mechanics was developed by Erwin Schrodinger
• Estimates the probability of finding an e- in a certain position
• Electrons are found in an “electron cloud” or orbital
Radial Distribution CurveOrbital
Orbital (“electron cloud”)– Region in space where there is 90% probability of
finding an e-
Each orbital letter has a different shape.
“s” orbitalspherical shaped, and holds up to 2e-
“p” orbitalDumbbell shapedArranged x, y, z axes, and canhold up to 6e-
“d” orbitalclover shaped, and can hold upto 10e-
“f” orbital
f
• Orbitals combine to form a spherical shape.
• This orbital can hold up to
14e-
2s
2pz2py
2px
Hog HiltonYou are the manager of a prestigious new hotel in downtown
Midland—the “Hog Hilton”. It’s just the “snort of the town” and you want to keep its reputation a cut above all the other hotels. Your problem is your clientele. They are hogs in the truest sense.
Your major task is to fill rooms in your hotel. The Hog Hilton only has stairs. You must fill up your hotel keeping the following rules in mind:1) Hogs are lazy, they don’t want to walk up stairs!2) Hogs want to room by themselves, but they would rather room with another hog than walk up more stairs.3) If hogs are in the same room they will face in opposite directions.4) They stink, so you can’t put more than two hogs in each room.
Hog Hilton• Your hotel looks like the diagram below:
6th floor ______5th floor ______ ______ ______ 4th floor ______3rd floor ______ ______ ______2nd floor ______1st floor ______
Book 7 hogs into the rooms.
Hog HiltonYour hotel looks like the diagram below:
6th floor ______5th floor ______ ______ ______ 4th floor ______3rd floor ______ ______ ______2nd floor ______1st floor ______
Book 14 hogs into the rooms.
Let’s play Hog Hilton!!
Rules for e- configurations1. Aufbau principle: e- enter orbitals of lowest energy
level (Hogs are lazy, they don’t want to walk up stairs!)
2. Pauli exclusion principle: an atomic orbital may have at most 2 e-, e- in the same orbital will spin in opposite directions (They stink, so you can’t put more than two hogs in each room. & If hogs are in the same room they will face in opposite directions.)
3. Hund’s rule: when e- occupy orbitals of = energy, 1 enters each orbital until all the orbitals contain 1 e- w/parallel spins (Hogs want to room by themselves, but they would rather room with another hog than walk up more stairs.)
Now you will relate the “Hog Hilton” to electron orbitals. Electron orbitals are modeled by the picture on the left and are grouped into principal energy levels.
1. Compare their similarities and differences.2. To go between floors on the Hog Hilton did the hogs need to use energy? Would electrons
need to use the energy to go between orbitals.
3d ___ ___ ___ ___ ___ n=3(4s ____) n=43p ___ ___ ___ n=33s ___ n=32p ___ ___ ___ n=22s ___ n=21s ___ n=1
6th floor ___5th floor ___ ___ ___4th floor ___3rd floor ___ ___ ___2nd floor ___1st floor ___
A. The principle quantum numbers, (n)• Electrons are in designated energy levels.
Organization of e- in the Quantum Mechanical model
The ground state- the lowest energy state of the atom
B. Within the energy level are sublevels, designated by letters.
Principle energy level
(n)
Number of
sublevels
Type of Orbital
1st energy level
1 sublevel “s” (1 orbital)
2nd 2 sublevels
“s” (1) & “p” (3 orbitals)
3rd 3 sublevels
“s”(1) , “p” (3) & “d” (5 orbitals)
4th 4 sublevels
“s”(1), “p”(3) , “d”(5), and “f” (7)
1s
2s2p
3p3s
4s3d
4p5s
4d5p
6s4f
5d6p7s
7s 7p6s 6p 6d 6f 6g5s 5p 5d 5f 5g4s 4p 4d 4f3s 3p 3d2s 2p1s
Filling in orbitals then writing the electron configuration
4p _ ↑↓ _ _ ↑↓ _ _ ↑↓ _3d _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ _ ↑↓ _4s _ ↑↓ _3p _ ↑↓ _ _ ↑↓ _ _ ↑↓ _3s _ ↑↓ _2p _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ 2s _ ↑↓ _ 1s _↑↓_ 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
1. Noble Gases – outermost s & p sublevels filled
Because they have their s2 & p6 orbitals filled they
follow the:2 + 6 = OCTET RULE
D. According to their e- configs, elements can be classified into 4 main groups
2. Representative Elements – outermost s or p sublevel is only partially filled, energy level same as period #The pink elements excluding the Noble Gases.s1 s2
p1 p2 p3 p4 p5
3. Transition metals – outermost s sublevel & nearby d sublevel contain e- , energy level is the same as the period # minus 1
d1 d2 d3 d4 d5 d6 d7 d8 d9 d10
4. Inner Transition metals - outermost s & nearby f generally contain e-
f1 f14
d1 d2 d3 d4 d5 d6 d7 d8 d9 d10
f1 f14
s1 s2
p1 p2 p3 p4 p5 s2
p6
Your Periodic Table should look like this.
How many electrons are present in the d sublevel of a neutral atom of Manganese?
Learning Check
1 2 3 4 5
5 electrons
What element has the electron configuration 1s22s22p63s23p4?
Add together all the exponents, then find that atomic number. = Sulfur 16
E. Using the Noble Gases to write Shorthand
• Write the noble gas that is in the previous row. • Use the symbol of the noble gas, put it in brackets,
then write the rest of the configuration.
• Write the e- config for Tin (Sn). • [Kr] 5s2 4d10 5p2
Write the e- config using Noble Gas notation for Cobalt.It would be written [Ar] 4s2 3d7
Learning CheckUsing the Noble Gas Shorthand write the e- configuration
1. Cr
2. Br
3. Te
4. Ba
[Ar] 4s2 3d4
[Ar] 4s2 3d10 4p5
[Kr] 5s2 4d10 5p4
[Xe] 6s2
Electromagnetic Spectrum• The electromagnetic spectrum (see p. 373) includes radio
waves, microwaves, infrared waves, visible light, ultraviolet waves, x-rays, and gamma rays.
• Visible light is in the middle of the spectrum.• The speed of light is 3.0 X 108 m/s.
• The formula for light is c =ƛʋ• C = speed of light, ƛ = wavelength, ʋ = frequency– Visible light has many wavelengths of light that can be
separated into red, orange, yellow, green, blue, indigo, and violet (ROY G BIV)
Atomic Emission Spectrum
• Every element gives off light when it is excited by the passage of an electric current through its gas or vapor.
• The atomic emission spectrum occurs when the light that is given off by an element in its excited state is passed through a prism. It consists of a few lines called a line spectra or discontinuous spectra. Each line on the spectra corresponds with a frequency.
Planck’s Constant
• In 1900, German Physicist Max Planck used math to explain why objects, such as iron, that are heated change color.
• He said energy can be quantized. The size of an emitted or absorbed quantum depends on the size of the energy change. A small energy change involves the emission or absorption of low frequency radiation. A large energy change involves the emission or absorption of high frequency radiation.
Planck’s constant cont.
• The math formula used is:
E = h x vE = radiant energy of a unit (quantum)h = Planck’s constant = 6.6262 x 10 -34
v = frequency of radiation
Planck’s constant cont.
• In 1905, Albert Einstein used Planck’s work to call quanta of light photons. He then used this information to explain the photoelectric effect (metals eject/emit electrons called photoelectrons when light shines on them).