DOR: Periodic Trends
Circle the element with the LOWEST ionization energy
1) Potassium, Calciucm
2) Nitrogen, Fluorine
Circle the element with the SMALLEST atomic radii
3) Li, Cs
4) K, Br
Nuclear Chemistry
Radioactive Decay
Spontaneous breakdown of an atom’s nucleus
Breakdown results in a lighter nucleus
Emits electromagnetic radiation
Nuclear radiation—radiation emitted from nucleus
Radioactive nuclide– nucleus that goes through
radioactive decay, unstable. (Ex. Uranium)
What is a nuclide
Radioactive nuclide–
nucleus that goes through radioactive decay
unstable
Contains a certain amount of energy
Ex. Uranium
Types of Radioactive Decay
1) Alpha particle (α)
Consists of 2 protons, 2 neutrons emitted during decay
SO atomic # decreases by 2 and atomic mass decreases by
4
Helium nucleus ( 24He )—how particle represented
Can be stopped by paper, low penetrating power
Equation: 84210 Po 
206
82
Pb + 24 He
Types of Radioactive Decay
(cont.)
2) Beta particle (β)
Releases beta particles (electron given off during radioactive decay)
Negative charge causes deflection
Can be stopped by lead or glass
Increase in atomic # by 1, NO change in atomic mass
Neutron converts to proton and electron
Gaining proton, no lose in mass because neutron converted to proton—
same mass
Equation: 614 C 
14 N
7
+ -10 β
Types of Radioactive Decay
(cont.)
3) Gamma Rays
Has the most energy, only stopped by lead, high penetrating
power
Releases gamma rays (γ) from nucleus
Type of electromagnetic radiation
Composed of photons, released as excited nuclei fall to lower
energy level
Ex. X-Rays
Types of Radioactive Decay
(cont.)
4) Positron Emission
•
Release of positrons
•
positrons—
•
•
Similar to electrons, have a positive charge
Creates two gamma rays—when contact with electron
•
Proton converted to neutron and positron
•
Atomic # decreases by 1 due to losing proton, no mass #
change
•
Ex. 2613Al 
26 Mg
12
+ 01e
Example 1: Nuclear equation
when an alpha particle emitted
by 21084Po
Example 2:Nuclear equation
when a beta particle emitted by
210 Pb
82
Practice: Alpha Decay
1) Be-9
2) U-238
3) Eu-154
Beta Decay
1) Th-234
2) K-43
Half-Life
Time period required for half of a radioactive nuclide to
decay.
Vary depending on the nuclide, unique for each nuclide.
Radioactive decay series—
chain of radioactive decays
Begins with radioactive nuclei and ends with nonradioactive
nuclei
Ex. U-238
Ex. 146C has a half-life of 5715. Therefore, if we have 10g of
14 C, in 5715 years we will have 5g.
6
Some sources say 5730 years (course textbook)
Half-Life (cont.)
Random decay process
Radioactive decay law—
Rate of radioactive decay proportional to # of atoms
present in sample
Half-Life Equation
AE = AO * 0.5
t/t(1/2)
AE = Substance amount
A0 = Initial substance amount
t = time elapsed
t1/2 = half-life
Example 1: Plutonium-239 has a half life of 24,110 years.
We have 100g of this substance. How many grams will we
have after 96,440 years?
Nuclear Chemistry Practice
Worksheet
1) Lawrencium has a half-life of 10 hours. We have a 5
gram sample of this element. How much of this sample
did we have 25 hours ago.
2) Actinium has a half-life of approximately 22 years.
We now have a sample of 35 grams. How much of this
sample will we have in 60 years?
3) Write the alpha equation for 23290 Th
4) Write the beta equation for 21083 Bi
AP CHEMISTRY EXAM
FORMAT
Curriculum
Focused on 6 “Big Ideas” that are broken down into
“Enduring Understanding” and “Essential Knowledge”
standards for the course.
Big Ideas:
Big Idea 1: Study of Matter
Big Idea 2: Chemical Bonding
Big Idea 3: Chemical Reactions
Big Idea 4: Kinetics
Big Idea 5: Thermodynamics
Big Idea 6: Chemical Equilibrium
Big Ideas Broken Down
Kinetics
Gas Equilibrium
Acid/Base Equilibrium
Electrochemistry
Thermochemistry
Ksp and limited solubility
AP Exam
2 sections:
One multiple choice– 90 minutes
One free-response— 90 minutes
Focus on data interpretation, modeling, conceptual
explanations, experimental procedure.
50% of score on Multiple Choice, 50% on FreeResponse
AP Exam (cont.)
Section I—Multiple Choice Section
60 questions
Analysis of data sets
No calculator permitted
Lots of visuals, graphs, and data
Section II—Free-Response Section
Calculators permitted
Short and long responses (approx. 3-4 questions each)
Focus: experimental design, data analysis, molecular
diagrams—explanation of these concepts
Spend approximately 20 minutes on each question
Tips for the AP Exam
Be concise in your answer!
Write in ink
Box in your final answer !
Keep it organized
Budget your time
1st 15/last 15—easiest, more thought questions tend to be in the middle
You do NOT have that much time to calculate an answer
Label everything (answer, work, etc,)
Do NOT restate the question—ANSWER it!
No penalty for guessing, answer ALL questions
ALWAYS provide some set-up procedure and give correct units for your
answer
DO NOT JUST PUT ANSWER DOWN
Labs
Pay Attention to the lab procedures we utilize—what
equipment is used, how to perform an experiment for a
particular chemical concept
Calorimetry---heat of reaction
Titration—Acid/Base
Determination of Chemical Formula—Empirical
Formula
Mass spectrometry—isotope mass
Liquid chromatography—mixture separation
DOR: Nuclear Chemistry
Write the following nuclear equations.
1) Alpha decay of Ir—174
2) Beta decay of platinum—199
More on Nuclear
Chemistry
Nuclear Fission
Nuclear reaction where nuclei are SPLIT
Nucleus is broken down into a more stable nucleus
heavy nucleus is broken into lighter fragments
HUGE amount of energy is released
Critical mass = minimum number of nuclei that can provide enough
neutrons to maintain chain reaction, results in nuclear explosion.
Nuclear reactors = controlled fission reactions.
**Can induce a nuclear chain reaction!!!
Fission (cont.)
Thermal neutrons bombard U-235
Mass is converted to energy
8 x 10 7 kJ/g
More energy than burning coal
Energy can be utilized !
First reaction causes the splitting of 2 more U-235
nuclei—generates a chain reaction
Nuclear Reactors
Location where controlled fission reactions occur
Fuel rods in the core contain enriched uranium
Steam generation
generator
steam turbine
electric
Control rods take in neutrons so fission is controlled
Production of radioactive waste
A TON of water is used to cool the reactors
Nuclear Fusion
Nuclei having a light mass are joined.
Combination of light nuclei
Creates heavy nucleus
Results in larger, stable nucleus.
MORE energy released than in nuclear fission !!!
Hard to control
Initiated by fission reaction (fission bomb) ---- H bomb
**Type of reaction happening in the sun and stars.
-fuel: hydrogen atom
cu
Applications
•
Diagnostic
•
1) Radioisotopes
•
•
•
2) Ionizing radiation
•
•
•
•
Actual substance or modified into biological substance for organ targets
Ex. Technetium
Both cancer causing and cancer treatment
Use of gamma rays to target tissue
Ex. Co-60
Ingestion of Radioactive Chemical
•
•
Migrates to target tissue
Ex. Iodine for thyroid
Applications (cont.)
•
Radiation processing
•
•
•
•
Used with medical supplies and food
Treated with ionized radiation
Kills microorganisms
Radioactive Tracers
•
•
Attach or “tag” to other substances
Enables monitoring substance process or substance detection
Homework
Read lab procedure on liquid chromatography
Read pp. 799-807, 815-823
DOR: Liquid
Chromatography
1)
The ___________ phase is when the mixture is added to
the chromatography column and attaches to the substrate.
2)
The __________ phase occurs when a solvent is passed
through the chromatography column to transport mixture
components out of the chromatography column.
3)
Name the type of chromatography column we will be using
in lab.
4)
How should you add the 10 ml of 18% isopropanol
solution to the chromatography column?
5)
How many trials are you doing?