Chapter 5 Quantum Mechanical Model

1. Chapter 5 Quantum Mechanical Model Electron Configuration

2. 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

3. Radial Distribution Curve Orbital Orbital (“electron cloud”) • Region in space where there is 90% probability of finding an e-

4. Each orbital letter has a different shape.

5. “s” orbital spherical shaped, and holds up to 2e-

6. “p” orbital Dumbbell shaped Arranged x, y, z axes, and can hold up to 6e-

7. “d” orbital clover shaped, and can hold up to 10e-

8. 2s 2px 2py 2pz f “f” orbital • Orbitals combine to form a spherical shape. • This orbital can hold up to • 14e-

9. Hog Hilton You 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.

10. 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.

11. Hog Hilton Your hotel looks like the diagram below: 6th floor ______ 5th floor ______ ______ ______ 4th floor ______ 3rd floor ______ ______ ______ 2nd floor ______ 1st floor ______ Book 14 hogs into the rooms.

12. Let’s play Hog Hilton!!

13. Rules for e- configurations 1. 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.)

14. 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=4 • 3p ___ ___ ___ n=3 • 3s ___ n=3 • 2p ___ ___ ___ n=2 • 2s ___ n=2 • 1s ___ n=1 6th floor ___ 5th floor ___ ___ ___ 4th floor ___ 3rd floor ___ ___ ___ 2nd floor ___ 1st floor ___

15. Organization of e- in the Quantum Mechanical model A. The principle quantum numbers, (n) • Electrons are in designated energy levels. The ground state- the lowest energy state of the atom

16. B. Within the energy level are sublevels, designated by letters.

17. 7s 6p 5d 4f 6s 5p 7s 7p 6s 6p 6d 6f 6g 5s 5p 5d 5f 5g 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s 4d 5s 4p 3d 4s 3p 3s 2p 2s 1s

18. Filling in orbitals then writing the electron configuration 4p _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ 3d _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ 4s _ ↑↓ _ 3p _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ 3s _ ↑↓ _ 2p _ ↑↓ _ _ ↑↓ _ _ ↑↓ _ 2s _ ↑↓ _ 1s _↑↓_ • 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6

19. D. According to their e- configs, elements can be classified into 4 main groups 1. Noble Gases – outermost s & p sublevels filled Because they have their s2 & p6 orbitals filled they follow the: 2 + 6 = OCTET RULE

20. 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

21. 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

22. 4. Inner Transition metals - outermost s & nearby f generally contain e- f1 f14

23. Your Periodic Table should look like this. s1 s2 p1 p2 p3 p4 p5 s2 p6 d1 d2 d3 d4 d5 d6 d7 d8 d9 d10 f1 f14

24. Learning Check How many electrons are present in the d sublevel of a neutral atom of Manganese? 1 2 3 4 5 5 electrons

25. What element has the electron configuration 1s22s22p63s23p4? Add together all the exponents, then find that atomic number. = Sulfur 16

26. 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 using Noble Gas notation for Cobalt. It would be written [Ar] 4s2 3d7 • Write the e- config for Tin (Sn). • [Kr] 5s2 4d10 5p2

27. Learning Check Using 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

28. 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)

29. 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. • See page 374. • Work problems # 11 and 12 on page 375.

30. 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.

31. Planck’s constant cont. • The math formula used is: E = h x v E = radiant energy of a unit (quantum) h = Planck’s constant = 6.6262 x 10 -34 v = frequency of radiation

32. 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). • Work problems 13 and 14 on p. 379.