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DO NOT LEAVE CLASS WITHOUT YOUR DAILY TRACKER CHECKED! Date: _________________

5.1 Class WorkNuclear chemistry involves which two subatomic particles?

(1) Protons and neutrons(2) Protons and electrons(3) Electrons and neutrons(4) Positrons and electrons

KEY WORDS AND SYMBOLS:

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Stability of an isotope is based on the ratio of(1) protons and neutrons(2) protons and electrons(3) electrons and neutrons(4) positive charges to negative charges


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For most atoms with an atomic number less than 20, nuclear stability occurs when the ratio of neutrons to protons is 1:1. Which of the following atoms would be most likely to have an unstable nucleus?


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Which of these atoms does not have a 1:1 proton to neutron ratio and is not likely to be stable?

(1) C-12(2) N-14(3) Li3

7 (4) O816


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“Success is not the result of spontaneous combustion. You must set yourself on fire.”


5.1 Class WorkComparing Nuclear Decay

Fill in the following information based on the reference table:Types of Radiation

Type of radiation

Name of Particle

Notation Symbol Charge Mass (amu)

Penetrating Power

Alpha radiation

4 amu Low

Beta radiation

1/1836 amu

Moderate

Positron Emission

1/1836 amu

Moderate

Gamma Radiation

0 amu Very High

Which type of radioactive emission has a positive charge and weak penetrating power?

(1) alpha particle(1) beta particle(2) gamma ray(3) neutron


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Which of the following would be attracted toward a negatively charged sheet of metal?

(1) alpha particle(2) beta particle(3) gamma ray(4) none of the above


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Which of the following would be attracted toward a negatively charged sheet of metal?

(1) alpha particle(2) beta particle(3) gamma ray(4) none of the above


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5.2 Class Work

Natural Transmutation Artificial Transmutation

Label the following reactions as either natural or artificial transmutation and explain why:

1. _____________________________________________________

Why:

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Why:

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Why:

4. ______________________________________________________

Why:

A change that is undergone by an atom of an element made radioactive by bombardment with high-energy protons is called:

(1) natural transmutation(2) artificial transmutation(3) natural decay(4) radioactive decay


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5.2 Class WorkWhat is the name of the process in which the nucleus of an atom of one element is changed into a different element?

(1) decomposition(2) transmutation(3) substitution(4) reduction


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Which nuclear equation represents a natural transmutation?


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The change that is undergone by an atom of an element made radioactive by bombardment with high-energy protons is called

(1) natural transmutation(2) artificial transmutation


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Which equation is an example of artificial transmutation?


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5.3 Class WorkNuclear Fission:

Nuclear Fusion:



Label the following as either examples of fission or fusion

1. _____________________________________________________

2. _____________________________________________________

5.3 Class WorkWhich balanced equation represents nuclear fusion? KEY WORDS AND SYMBOLS:

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The energy released from a nuclear reaction results primarily from the(1) breaking of bonds between atoms(2) formation of bonds between atoms(3) conversion of mass into energy(4) conversion of energy into mass


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A nuclear fusion reaction and nuclear fission reaction are similar because both reactions

(1) Form heavy nuclides from light nuclides(2) Form light nuclides from heavy nuclides(3) Release a large amount of energy(4) Absorb a large amount of energy


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Answer here (short answer response):

a.

b.

c.

5.3 Class Work

Real-World examples of fission and fusion:

1. Summarize each scenario in 1-2 sentences.2. Determine if the reaction depicts fission or fusion.



3. Write out the nuclear reaction associated with the scenario (the answers are posted on the next page—but not in the correct order. Match the reaction on the next page to each scenarios

Nuclear Power Plant: Uranium-235 is used as the fuel for the nuclear power reaction as it is naturally radioactive, and is therefore unstable enough to be broken down into smaller parts. In a nuclear power plant, a neutron is shot at the uranium atom causing it to split into Ba-142, Kr-91 and 3 neutrons. The neutrons then cause other U-235 atoms to split. A tremendous amount of energy is released. This energy becomes heat energy as the particles slow down, and it is this heat energy, which is used to produce electricity. The heat is moved through a transfer medium, such as water, and is used to turn water into steam. This steam turns a turbine, which is connected to a generator. As the turbine turns the generator it creates electricity, which is then transferred to the consumers.

Summary:

Circle 1: FISSION OR FUSION

Nuclear Reaction:

Atomic Bomb: The first atomic bombs dropped to kill humans exploded in 1945 over the Japanese cities of Hiroshima and Nagasaki. Roughly 70,000 people died instantly at Hiroshima and another 70,000 died within four months of the explosion due to radioactive particles in the area. In an atomic bomb, a radioactive isotope such as U-235 is compressed together and then bombarded with 1 neutron. This causes the isotope to split into smaller isotopes—for example: Cs-140 and Rb-92 and two more neutrons. These neutrons then hit other atoms of Pu-239 causing a chain reaction. The amount of energy released from the earliest atomic bombs was equivalent to 20,000 tons of TNT. Today’s atomic bombs produce thousands of times this amount of energy.

Summary:


Nuclear Reaction:

5.3 Class Work

Hydrogen Bomb: Hydrogen bombs are the most powerful and deadly weapon ever invented by humanit. They can produce explosions equivalent of 10,000,000 tons of TNT.

Summary:



Hydrogen bombs take an explosion of an atomic bomb to provide the energy to detonate. In this reaction, H-2 and H-3 fuse together to form He-4 and an extra neutron. In this process an immense amount of energy is released. The blast of a hydrogen bomb could potentially destroy everything within 100 square miles and cause damage within 400 square miles.


Nuclear Reaction:

The Sun: The sun is a typical average star. It is large enough to fit 1.3 million Earths. It provides the energy for most things on Earth to live. The sun works by generating a nuclear reaction. At the core, the sun is 15,000,000 degrees C. There is so much heat and pressure inside the sun due to its intense gravity that atoms are formed from smaller atoms smashing together. One reaction inside the sun is as follows: Two protons combine to form Hydrogen-2 and a positron. Much energy is also produced. Ultimately these reactions inside the sun and other stars are responsible for forming all of the atoms in our Universe.

Summary:


Nuclear Reaction:

Answers (out of order):p1

1 + + p11 H12 + β+1

0

H12 + + H13 He24 + n01

U92235 + + n01 Kr36

91 + Ba56142 + 3 n01

U92235 + + n01 Cs55

140 + Rb3792 + 4 n01

5.4 Class Work



In the reaction 23892U X + 4

2He, the particle represented by X is

(1) 23490Th

(2) 23492U

(3) 23893Np

(4) 24294Pu


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Identify the missing particle in the following reaction: 23994Pu 42He + _______

(1) 23592U(2) 24396Cm(3) 23596Cm(4) 24392U


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5.4 Class Work




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An element with atomic number 88 goes through alpha decay. Its atomic number is now ______

A) 84.B) 88.C) 86.D) 80.


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5.5 Class WorkExample 1:

If 1.00 gram of a 16.00-gram sample of sodium-25 remains unchanged after 237 seconds, what is the fraction remaining?

Step 1: What was the mass of the original sample?

Step 2: What is the mass that is remaining after the given period of time?

Step 3: What is the fraction remaining?

Example 2:

An original sample of the radioisotope fluorine-21 had a mass of 80.0 milligrams. Only 20.0 milligrams of this original sample remain unchanged after 8.32 seconds. What is the fraction remaining after 8.32 seconds?

Figuring out the number of half-lives:

Once we figure out the fraction remaining, we can figure out how many half-lives have passed.



5.5 Class Work

Example 3:

If 1.00 gram of a 16.00 gram sample of sodium-25 remains unchanged after 237 seconds, how many half-lives have passed?

Step 1: What was the mass of the original sample?

Step 2: What is the mass that is remaining after the given period of time?

Step 3: What is the fraction remaining?

Step 4: How many half-lives have passed?

Example 4:

An original sample of the radioisotope fluorine-21 had a mass of 80.0 milligrams. Only 20.0 milligrams of this original sample remain unchanged after 8.32 seconds. How many half-lives have passed?



5.5 Class Work

Example 5:

A sample of wood is found to contain 1/8 as much C-14 as is present in the wood of a living tree. How old is the tree?

Step 1: Figure out the fraction remaining.

Step 2: Figure out the number of half- lives passed.

Step 3: Figure out the length of one half-life (Table N or given in the problem).

Step 4: Multiply the number of half-lives by the length of one half-life.

Example 6:

How many days are required for 200. grams of radon-222 to decay to 50.0 grams?

Example 7: (A little different, but just think about it!)

An original sample of the radioisotope fluorine-21 had a mass of 80.0 milligrams. Only 20.0 milligrams of this original sample remain unchanged after 8.32 seconds. What is the half-life of fluorine-21?



5.5 Class Work


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What is the mass of K-42 remaining in a 16-g sample of K-42 after 37.2 h?(1) 1.0g(2) 2.0g(3) 8.0g(4) 4.0g


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5.5 Class Work1. If a scientist purifies 1.0 gram of radium-226, how many years must pass before only 0.50 gram of the original

radium-226 sample remain unchanged?

2. In living organisms, the ratio of the naturally occurring isotopes of carbon, C-12 to C-13 to C-14, is fairly consistent. When an organism such as a woolly mammoth died, it stopped taking in carbon, and the amount of C-14 present in the mammoth began to decrease. For example, one fossil of a woolly mammoth is found to have 1/12 of the amount of C-14 found in a living organism.

a) Identify the type of nuclear reaction that caused the amount of C-14 in the woolly mammoth to decrease after the organism died.



b) Determine the total time that has elapsed since this woolly mammoth died.

c) State, in terms of subatomic particles, how an atom of C-13 is different from an atom of C-12.

5.5 Class Work

3. Some radioisotopes used as tracers make it possible for doctors to see the images of internal body parts and observe their functions. The table below lists information about three radioisotopes and the body part each radioisotope is used to study.

a) Write the nuclear decay equation used to study red blood cells.



b) It could take up to 60. hours for a radioisotope to be delivered to the hospital from the laboratory where it is produced. What fraction of an original sample of 24Na remains unchanged after 60 hours?


DO NOT LEAVE CLASS WITHOUT YOUR DAILY TRACKER CHECKED! Date: _______________

5.6 Class WorkRead the following stories of how real-life radioactive isotopes are used in everyday life. Then write the balanced nuclear reaction that occurs in each scenario:

Cancer Treatment:

When living tissue is exposed to high levels of radiation, cells can be destroyed or damaged so they can neither reproduce nor continue their normal functions. For this reason radioisotopes are used in the treatment of cancer (which amounts to uncontrolled cell division). Although some healthy tissue surrounding a tumor may be damaged during the treatment, mostly cancerous tissue can be targeted for destruction. A device called a teletherapy unit destroys malignant tumors with gamma radiation from a radioisotope such as cobalt-60 (Co-60). Teletherapy units use a high-energy beam of gamma rays to reduce or eradicate tumors deep within the body. These units are licensed by the NRC because they use byproduct material that is produced only by a nuclear reactor.

Balanced Nuclear Reaction:

Internal Body Imaging:

Positron Emission Tomography (PET) is a precise and sophisticated technique using isotopes to help make images of a functioning body part. A positron-emitting radionuclide is introduced, usually by injection, and accumulates in the target tissue. As it decays it emits a positron, which promptly combines with a nearby electron resulting in the simultaneous emission of two identifiable gamma rays in opposite directions. These are detected by a PET camera and give very precise indication of their origin. PET's most important clinical role is in cancer detection, with fluorine-18 as the tracer, since it has proven to be the most accurate non-invasive method of detecting and evaluating most cancers. It is also well used in cardiac and brain imaging.


Thyroid monitoring:

Radiation is used to both detect and treat abnormalities in the body. Iodine-131 can be used in a diagnostic procedure to monitor the function of the thyroid. The rate at which the thyroid rakes up the iodine-131 can be monitored with a scanning device to see if it is functioning properly. Iodine, whether it's radioactive or not, goes right to the thyroid, where it is incorporated into the amino acid thyroxine (the only molecule in the body that contains iodine). Therefore, iodine-131 is perfect for monitoring the thyroid gland. The radiation from I-131 can also be used to destroy any thyroid cancer cells.


Determining how long ago something lived:

Animals and plants have a known proportion of Carbon-14 (a radioisotope of Carbon) in their tissues. When they die they stop taking Carbon in, then the amount of Carbon-14 goes down at a known rate (Carbon-14 has a half-life of 5700 years). The age of the ancient organic materials can be found by measuring the amount of Carbon-14 that is left. This technique makes accurate measurements up to about 50,000 years ago. There are other radioactive isotopes that are accurate for times beyond this.




5.6 Class WorkQuestion Explanation of Answer

The decay of which radioisotope can be used to estimate the age of the fossilized remains of an insect?

a) Rn-222b) Co-60c) I-131d) C-14


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Which radioisotope is used to treat thyroid disorders?

a) Co-60b) I-131c) C-14d) U-238


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The radioisotope I-131 is used toa) control nuclear reactorsb) determine the age of fossilsc) diagnose thyroid disordersd) trigger fusion reactors


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The radioactive isotope carbon-14 can be used for

a) determining the age of a sampleb) determining medical disordersc) controlling fission reactionsd) controlling speeds of neutrons


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