AP Chemistry Readiness Light Review Page 1 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service

AP Chemistry Review Session November 14, 2015

UCLA Michael A. Morgan Richard Erdman Larry Walker mmorgan@lausd.net xchemteach@yahoo.com walker@lvusd.org Francisco Bravo Medical Magnet High School Venice High School (Emeritus) Calabasas High School Waves Wave Properties

Name Symbol Unit Definition

Wavelength

Frequency

Period

Amplitude

Wave Number

Now on to Light

AP Chemistry Readiness Light Review Page 2 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service The Speed of Light is given the symbol c. C =3.00 x 108 m/sec =3.00 x 1010 cm/sec =186,282 miles/sec = 299,792.458 km/sec The Electromagnetic Spectrum How do we solve the mathematical problems involving light?

c= λxν

Velocity(m/s)

Wavelength(m)

Frequency(Hz)

5.80x1014

5.00 x 10—7

5.20x1014

3.14

What is the frequency of some red light that has a wavelength of 650 nm's? What is the wavelength of tunes broadcast by the great 1970's station KMET-FM 94.7MHz?

AP Chemistry Readiness Light Review Page 3 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Max Planck

The fist quantum hypothesis h = 6.626x10-34Joule x seconds (not joules per second)

Velocity(m/s)

Wavelength(m)

Frequency(Hz)

Energy(J)

5.80x1014

5.00 x 10—7

4.75x10–19

What is the energy of a photon of light whose frequency is 5.50 x 1014 Hz? What is the energy of a mole of photons of red light whose wavelength is 700 nm’s? Photoelectric Effect Noun: Ejection of electrons from a substance by incident electromagnetic

radiation, especially by visible light.

AP Chemistry Readiness Light Review Page 4 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service In 1885 a Swiss School Teacher named Johann Balmer showed us the spectrum of Hydrogen:

This could be explained by a formula involving integer numbers. Another Swiss named Johannes Rydberg moved the formula forward to give us our current form: The constant equal to 109,680 cm-1, has many values in different units. The number nf can tell us how much energy is going to be associated with he light and where we are going to see the lines grouped together.

Name

nf

ni

Region of Electromagnetic Spectrum

AP Chemistry Readiness Light Review Page 5 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Niels Bohr 1911 and the gospel of the planetary atom. 1913- Chance and the prepared mind. Serendipity

What are the circles?

What were the magic four words? An electron jumps from the n=4 to the n=2 state what is the wavelength of the light emitted? Quantum Mechanics becomes a teenager. A bullet in Sarajevo changes everything.

AP Chemistry Readiness Light Review Page 6 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service The Nature of Matter A Prince has a crazy idea! Louis de Broglie How do you get out of fighting a war? 1924, a doctoral dissertation, and a Nobel Prize All matter is wavelike? The de Broglie Wavelength What is the de Broglie wavelength of an electron traveling at 90% of the speed of light? The mass of an electron is 9.11x10-31kg. What is the de Broglie wavelength of a baseball whose mass is 5 oz (0.14 kg) traveling at 90 mph (40 m/s)?

AP Chemistry Readiness Light Review Page 7 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service What is a standing wave?

Where is the electron likely to be found?

The Schrodinger Wave Equation Werner Heisenberg and The Uncertainty Principle Quantum Mechanics

AP Chemistry Readiness Light Review Page 8 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service The Quantum Numbers When we solve the Schrodinger Equation we get lots of correct answers. What do they mean? They are descriptions of the orbitals.

Quantum Number

Symbol

Values

Physical Meaning

What does a 1S orbital look like? What about a 2S orbital?

AP Chemistry Readiness Light Review Page 9 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service The Pauli Exclusion Principle

How do you work with Quantum Numbers?

L=

0

1

2

3

Orbital

How many orbitals are in the n=3 shell? What about n=2? How many orbitals are in the n=3 and l=2 subshell? How many orbitals can have the designation n= 2, l=1, and ml = 1? How many electrons can have the following designations: a. n = 2 L = 1 mL = +1 b. n = 4 L = 3 mL = +3 ms = 1/2 c. n = 5 L = 3 mL = +1 ms = -1/2 d. n = 4 L = 2 mL = +2 ms = 1/2 e. n = 5

AP Chemistry Readiness Light Review Page 10 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Aufbau Principle

Frederick Hund

AP Chemistry Readiness Light Review Page 11 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service 1H 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 2He 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 3Li 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 4Be 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 5B 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 6C 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 7N 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 8O 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 9F 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 10Ne1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 11Na1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 12Mg1S___2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 13Al 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 14Si 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 15P 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 16S 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 17Cl 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 18Ar 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 19K 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 20Ca1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 21Sc 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 22Ti 1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 23 V1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 24 Cr1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___ 25 Mn1S___ 2S___ 2P ___ ___ ___ 3S ___ 3P___ ___ ___4S ___ 3d ___ ___ ___ ___ ___

AP Chemistry Readiness Light Review Page 12 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Some Notable Exceptions Cr Cu/Cu2+ Mo Ag/Ag+ Au Polyelectronic Models Hydrogen versus Helium Effective Nuclear Charge and Shielding The Modern Periodic Table (Glenn Seaborg 1947)

AP Chemistry Readiness Light Review Page 13 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Periodic Properties Effective Nuclear Charge

Ionization Energy

0

1

2

3

4

5

1 2 3 4 5 6 7 8 9 10 11 12

Zef

f

Atomic number (Z)

Effective Nuclear Charge

H He Li Be B C N O F Ne Na

Extra repulsion due to doubly-occupied orbitals

No Screening Zeff = Z

H

He

Li

Be

B

C

N

O

F

Ne

Na

Mg

P

Ar

K

Zn As

Br

Kr

Rb

Cd

I

Xe

Cs

Tl

Rn

0

500

1000

1500

2000

2500

0 22 44 66 88

Ioni

zatio

n En

ergy

(Kj/m

ol)

Atomic Number

Ionization energy (Kj/mol)

Period 1

Period 2

Period 3

Period 4

Period 5

Period 6

AP Chemistry Readiness Light Review Page 14 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Electron Affinity

Atomic Radii

-400

-300

-200

-100

0

100

200

300

0 2 4 6 8 10 12 14 16 18 20

Ele

ctro

n A

ffin

ity (k

j/mol

)

Atomic number

Electron Affinity

AP Chemistry Readiness Light Review Page 15 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Spectroscopy Lab Spectroscopy Why is a liquid colored? Spectrophotometer

What happens when light travels through a medium? Beer's Law

AP Chemistry Readiness Light Review Page 16 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Calibration of the meter. What colors absorb what other colors? All measured in nanometers

AP Chemistry Readiness Light Review Page 17 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service Photoelectron Spectroscopy

AP Chemistry Readiness Light Review Page 18 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service

AP Chemistry Readiness Light Review Page 19 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service 2006 Suppose that a stable element with atomic number 119, symbol Q, has been discovered. (a) Write the ground-state electron configuration for Q, showing only the valence-shell

electrons. (b) Would Q be a metal or a nonmetal? Explain in terms of electron configuration. (c) On the basis of periodic trends, would Q have the largest atomic radius in its group or would

it have the smallest? Explain in terms of electronic structure. (d) What would be the most likely charge of the Q ion in stable ionic compounds? (e) Write a balanced equation that would represent the reaction of Q with water. (f) Assume that Q reacts to form a carbonate compound.

(i) Write the formula for the compound formed between Q and the carbonate ion, CO32–.

(ii) Predict whether or not the compound would be soluble in water. Explain your reasoning.

2007

First Ionization Energy

(kJ mol-1)

Second Ionization Energy

(kJ mol-1)

Third Ionization Energy

(kJ mol-1) Element 1 1,251 2,300 3,820 Element 2 496 4,560 6,910 Element 3 738 1,450 7,730 Element 4 1,000 2,250 3,360

The table above shows the first three ionization energies for atoms of four elements from the third period of the periodic table. The elements are numbered randomly. Use the information in the table to answer the following questions. (a) Which element is most metallic in character? Explain your reasoning. (b) Identify element 3. Explain your reasoning. (c) Write the complete electron configuration for an atom of element 3. (d) What is the expected oxidation state for the most common ion of element 2? (e) What is the chemical symbol for element 2? (f) A neutral atom of which of the four elements has the smallest radius? 1997 Explain each of the following observations using principles of atomic structure and/or bonding. (a) Potassium has a lower first-ionization energy than lithium. (b) The ionic radius of N3- is larger than that of O2-. (c) A calcium atom is larger than a zinc atom. (d) Boron has a lower first-ionization energy than beryllium.

AP Chemistry Readiness Light Review Page 20 of 20 Copyright by Michael A. Morgan Except Former AP Questions Copyright by Educational Testing Service 2007 Answer the following problems about gases. (a) The average atomic mass of naturally occurring neon is 20.18 amu. There are two common

isotopes of naturally occurring neon as indicated in the table below.

Isotope Mass (amu) Ne-20 19.99 Ne-22 21.99

(i) Using the information above, calculate the percent abundance of each isotope. (ii) Calculate the number of Ne-22 atoms in a 12.55 g sample of naturally occurring neon.

(b) A major line in the emission spectrum of neon corresponds to a frequency of 4.34×1014 s-1. Calculate the wavelength, in nanometers, of light that corresponds to this line.

(c) In the upper atmosphere, ozone molecules decompose as they absorb ultraviolet (UV) radiation, as shown by the equation below. Ozone serves to block harmful ultraviolet radiation that comes from the Sun.

O3(g) UV! →! O2(g) + O(g) A molecule of O3(g) absorbs a photon with a frequency of 1.00×1015 s-1. (i) How much energy, in joules, does the O3(g) molecule absorb per photon? (ii) The minimum energy needed to break an oxygen-oxygen bond in ozone is 387 kJ mol-1.

Does a photon with a frequency of 1.00×1015 s-1 have enough energy to break this bond? Support your answer with a calculation.

1987 Two important concepts that relate to the behavior of electrons in atom systems are the Heisenberg uncertainty principle and the wave-particle duality of matter. (a) State the Heisenberg uncertainty principle as it related to the determining the position and

momentum of an object. (b) What aspect of the Bohr theory of the atom is considered unsatisfactory as a result of the

Heisenberg uncertainty principle? (c) Explain why the uncertainty principle or the wave nature of particles is not significant when

describing the behavior of macroscopic objects, but it is very significant when describing the behavior of electrons.

1981 D The emission spectrum of hydrogen consists of several series of sharp emission lines in the ultraviolet (Lyman series) in the visible (Balmer series) and in the infrared (Paschen series, Brackett series, etc.) regions of the spectrum. (a) What feature of the electronic energies of the hydrogen atom explains why the emission

spectrum consists of discrete wavelength rather than a continuum wavelength? (b) Account for the existence of several series of lines in the spectrum. What quantity

distinguishes one series of lines from another? (c) Draw an electronic energy level diagram for the hydrogen atom and indicate on it the

transition corresponding to the line of lowest frequency in the Balmer series. (d) What is the difference between an emission spectrum and an absorption spectrum? Explain

why the absorption spectrum of atomic hydrogen at room temperature has only the lines of the Lyman series.