Do Now:1. Find your new seat.2. Complete the do now on page 4-2 (top section titled “do now”)

Nuclear Chemistry

History• 1869 French chemist Antoine Henri

Becquerel discovered that uranium salts could fog photographic film plates•Marie Curie and Pierre Curie were then

able to show that rays emitted by uranium were the reason for the fogging of the plates•Marie named the particles in these rays

radioactive.

Nuclear Energy•Nuclear reactions release a tremendous

amount of energy.•More energy than chemical reactions.• This energy comes from changing the

nucleus of an atom.

Stable vs. Unstable

• The nucleus of an atom changes because it is unstable due to the number of neutrons that are contained in it• Interpreting Graphs•Unstable nuclei spontaneously emit

radiation

Particles of Nuclear Chemistry• In both fission and fusion reactions,

particles are given off as the nuclei change. • Table O gives the name, notation, and

symbol of the emission particles.

Table O

Mass

Charge

Most Frequent Particles

• Alpha• Symbol:• Mass:• Charge:• Penetrating Power: The lowest (stopped by

paper)• Ionizing power: The highest

The ionizing power measures how many ions are formed in a given area when the

radiation passes through it.

Most Frequent Particles

• Positron• Symbol:•Mass:• Charge:• Penetrating Power: Medium (Stopped

by hands) • Ionizing power: Medium

Most Frequent Particles

• Beta• Symbol:•Mass:• Charge:• Penetrating Power: Medium (Stopped

by hands) • Ionizing power: Medium

Most Frequent Particles

• Gamma• Symbol:•Mass:• Charge:• Penetrating Power: High (stopped by

Lead)• Ionizing power: Lower

Find your seat then start the do now

Two Types of Nuclear Reactions

• Fission Reactions (Radioactive decay): When an unstable nucleus is broken apart, energy is released. • Nuclear Power Plants

work because Uranium-235 can be broken down into smaller nuclei.

http://gurumia.com/tag/rooppur-nuclear-power-plant/

𝑈→ 𝐻𝑒24

92238 + h𝑇90234 𝐶→ 𝑒− 1

0614 + 𝑁714

Fusion Reactions

•When two nuclei are crunched together to make one nuclei, lots of energy is released. • A Hydrogen Bomb and the

Sun work on this type of reaction.

http://space.about.com/od/solarsystem/ss/visualtourss.htm

𝐻+ 𝐻1312 → 𝑛01 + 𝐻𝑒2

4

Changing of the nucleus• In both fission and fusion reactions, energy

is releases as the nuclei change.• The process of fission and fusion both

cause an unstable radioisotope to turn into a stable isotope of a different element• For all nuclear reactions mass is converted

into energy.

Natural Transmutation

• Without the presence of an another particle, the number of protons changes in an atom.

Artificial TransmutationA change in the number of protons caused by the

addition of a particle.

Natural transmutation

Artificial transmutation

Ion

Isotope

fission

fusion Penetrating Power

Ionizing Power

Nuclear Reaction Equations

Writing Nuclear Equations• Reactants – the left side of our equation• Products – the right size of our equation• - yields; the same as an equal sign in math• We use isotopic notation in all nuclear equations.

Ur235

92

Mass Number

Nuclear Charge

Same as atomic number!

Writing Nuclear Equations

___________42

21483 HeBi

When solving a nuclear equation, the top numbers have to equal across the arrow.

When solving a nuclear equation, the bottom numbers have to equal across the arrow.

Writing Nuclear Equations

Once you have both pieces, find the element symbol on

the Periodic Table.

___________23994

23993 PuNp

Writing Nuclear Equations

Find the Missing Particle

Writing Decay Equations

Table N of your Reference Tables

has a collection of decay modes for a

number of elements.

Writing Decay Equations

We use the information in

table N to write a decay equation

from scratch.

???22087 Fr

1. Find the element that is decaying in table N and find the decay mode

Step Example1. Find the

element that is decaying in table N and find the decay

mode

1. Find the element that is decaying in table N and find the decay mode

Step Example2. Use table O to

figure out what the notation of your

decay mode particle is

1. Find the element that is decaying in table N and find the decay mode

Step Example3. Write this in your equation

1. Find the element that is decaying in table N and find the decay mode

Step Example4. Solve just like before… the top

numbers must add up and the bottom numbers must add

up

1. Find the element that is decaying in table N and find the decay mode

Step Example5. Now that you have the atomic number of your

missing atom, use your periodic table to find out which

element it is.

Try some on your own…

I13153

C146H34K3756

Average Atomic Mass

Writing Isotopic Notation

• Practice writing isotopic notation for the following elements:

Oxygen with a mass number of 15Nitrogen with a mass number of 14

Lithium with 3 protons and 3 neutronsFluorine with 9 protons and 10 neutrons

Average Atomic Mass

•Look up the mass of chlorine: 35.453 amu

•How can we have a mass of 35.453? Half a proton? Half a neutron?•This is the average atomic mass.

Average Atomic Mass

If there were equal amounts of each element, we could find the average mass of

each isotope but... There are not equal amounts

116 C 12

6 C 136 C 14

6 C

11+12+13+14 = 50 /4 = 12.5 amu

Average Atomic Mass

Each isotope is present in different abundances (percentages)

C-12 is 98.93%C-13 is 1.07%

The percentages (and the corresponding decimals) are the

Relative Abundance

Step 1: Convert Percent to decimal (by dividing by 100).

C-12 is 98.93%C-13 is 1.07%

Step 2: Multiple each abundance by the mass of each isotope

C-12 is 98.93%C-13 is 1.07%

Step 3: Add together

C-12 is 98.93%C-13 is 1.07%

Most Abundant Isotope

• The most abundant isotope is the isotope that has a mass closest to the average atomic mass. • The higher the percent abundance, the more the

overall mass will be close to the mass of that isotope.

Now Let’s Practice…

• Show all work in finding the average atomic mass.• Also CIRCLE the most abundant isotope.

Uses of Radioisotopes

More Uses of Nuclear Chemistry

• Iodine-131: used in the treatment of thyroid cancer as iodine is absorbed by the thyroid gland

Carbon Dating• Carbon-14

is used to date once living organism

Dating Geological Formations

• Uranium-238 is used to date geological formation (rocks, earth’s layers, artifacts, etc)• U-238 decays to Pb-206

Cancer Treatment

• Cobalt-60 is used in treating cancer• 2013 marks the

60th anniversary of this technology

Using Radioactive Isotopes

Positives• Treat Cancer• Irradiate Food • Fusion creates more

energy than fission• Excellent energy

producer

Negatives• Biological exposure:• Too much radiation can

cause cancer• Birth defects

• Safe storage and disposal: • Some decay reactions

produce unsafe isotope products

• Nuclear Accidents

Using the Reference TablePlease open to TableN

Using Table N

We differentiate isotopes by

mass.

Specific Radioisotope of each element

How long it takes half of

the sample to decay.

The particles that are

spontaneously released during

decay.

Element

Mass of isotope

Half-Life Problems

Nuclear Decay

•Radioactive isotopes (radioisotopes) naturally decay over time•When radioisotopes decay they change to another isotope.

Half-life

•Half life is the amount of time it takes for half of a sample of a radioactive nuclide to decay

Example

Solving Half Life Problems

• To make solving half-life problems easier we can use the same chart every time (just plug in the correct numbers for each question).

We do: How long will it take for 30 g of Rn-222 to decay to 7.5 g?

We do: How many grams of N-16 will be left from a 16 g sample after 21.6 s?

We Do: The half life of cobalt 60 is 5.26 years. If 50g are left after 15.8 years, how many grams were in the original sample?

We do: If 100 g of Au-198 decays to 6.25 g in 10.8 days, what is the half-life of Au-198?

You Do

1. Try each of the problems in the practice section of your notes.

2. Ask 3 classmates for help before you ask Miss Shea.1. Remember: Helping looks like you explaining HOW to do the

problem, not you doing the problem for someone else.3. When finished, raise your hand and Miss Shea will check

your work

DebateBombs and Energy

Nuclear Bombs• The bomb has two parts: both parts hold critical

masses that when separated won’t produce fission.• When time to detonate the bomb, the foil between

the two parts is broken.• Now that the masses are combined, Polonium

begins to release alpha particles.• This causes a chain reaction where the alpha

particles collide with beryllium-9 to make beryllium-8 and free neutrons. • The neutrons initiate fission and the amount of heat

produced creates the bomb.

Nuclear States

Blue: Nuclear FreeRed: Nuclear Weapons

Orange: Nuclear Weapons ShareGold: None of the above

Hiroshima

Before

After

Over Exposure to Radiation

• Can cause:• Cancer (within bones, thyroid, lung, skin)• Alteration of tissue cells (fastest growing cells

the most, such as bone marrow)• Birth defects• Genetic mutations• Skin rashes, burns, or tissue death

• Effects are dependent on:• Amount of exposure• Length of exposure

iReflection Good ExampleI am very proud of the chemistry passing rate of 64% on this first interval. I feel that I did a few things to help the girls pass the exam. First, I provided a few days of review with a comprehensive review packet and practice questions. Second, I provided guided notes to help students pay attention and make it easier to get caught up. Third, I provided quite a bit of homework and would grade most assignments so students could get individual feedback. For the next interval, I will do a few things different. I will give homework and graded assignments back quicker. I will make sure more practice is regents questions based so the wording of the questions is more familiar. I will also make the do-now and exit slip assignments more productive and focused on content review.I believe that if I keep doing the actions I was doing before and make the changes I mentioned the passing rate will be much higher on the next interval exam.

iReflection Poor Example

I am proud of the passing rate for the chemistry exam. I think that because my students studied their study sheets, would do their independent homework assignments, and take notes on the guided notes they were able to pass the exam.

I think in order to better next quarter my students need to study a bit harder, come to me for extra help, and use the reference table more to get more answers.

iReflection RubricThree statements about actions that earned the grade

received. [3 points]Three statements about actions will do to do better next

quarter and interval. [3 points]Proper grammar, complete sentences, capitalization,

punctuation. [4 points]I statements used for each action. [6 points]Not talking and doing project individually. [4 points]