MONDAY (c) McGraw Hill Ryerson 2007. JOURNAL PROJECT YOUR JOURNAL WILL BE WORTH ___% OF THIS CHAPTERS GRADE EACH DAY YOU WILL BE REQUIRED TO ANSWER THE

•MONDAY

(c) McGraw Hill Ryerson 2007

JOURNAL PROJECT

YOUR JOURNAL WILL BE WORTH ___% OF THIS CHAPTERS GRADE• EACH DAY YOU WILL BE REQUIRED TO ANSWER THE INITIAL RESPONSE

QUESTIONS YOU WILL FIND ON THE PROJECTOR AT THE START OF CLASS, ONLY 10MIN WILL BE GIVEN TO COMPLETE THESE QUESTIONS.

• DURING MY LESSONS YOU WILL BE EXPECTED TO TAKE NOTES SUMMARIZING EACH SLIDE, A MINIMUM OF 2 FACTS WILL BE EXPECTED PER SLIDE.

• AT THE END OF THE DAY TIME WILL BE GIVEN TO WRITE A CONSIDERED RESPONSE. THIS IS WHEN YOU ANSWER THE SAME QUESTIONS FROM EARLIER APPLYING WHAT YOU HAVE LEARNED FROM CLASS. 10MIN WILL BE GIVEN.


JOURNAL EXAMPLE:

• Initial Response What do you think a cat looks like?

I would think that a cat is a large furry ball with 4 small legs• NOTES:

Slide One: Many people do not like cats Cleopatra liked cats a lot.

Slide Two: Cats are not very big Cats like to make meowing sounds.

• Considered response What do you think a cat looks like?

I now know that a cat is an animal with fur and it does have 4 legs. It also has a tail and whiskers. Cats like to eat small rodents like mice.

• . (c) McGraw Hill Ryerson 2007

March 31st Page One

INITIAL RESPONSE (MARCH 31)

• What do you think Radon is?

• What do you think Ionizing Radiation is?

• Do you think cell phones are harmful or not harmful to your health?

• What do you think Nuclear Medicine is?

• what do you think UV radiation is?


Agenda

• The circulatory System of a persons hand

• Enhanced with Radioactive Iron-59

• Why Iron?


Iron is taken up in the blood stream and is removed by the body a few months later.


7.1 Atomic Theory and Radioactive Decay

• Radioactivity is the release of high-energy particles or waves being emitted from a variety of materials.

When atoms lose high-energy particles or waves, ions or even new atoms can be formed.

When these High-energy waves or particles leave the atom they are called RADIATION!

See pages 286 - 287

Where do you think we find sources of radiation?

Natural Background Radiation

• Cosmic Radiation (FYI) The sun and stars send a constant stream of radiation to the earth


This Reaction is called Fission!


• Terrestrial Radiation (FYI)• The Earth itself is a source of

radiation. uranium , thorium and radium exist in soil

and rock. Essentially all air contains radon water contains small amounts of dissolved

uranium and thorium all organic matter (both plant and animal)

contains radioactive carbon and potassium. The amount of radiation from terrestrial sources varies in different parts of the world


Radioactive: Decays into calcium + e


• Internal Radiation (FYI) All of us have internal radiation, mainly from radioactive potassium-40 and carbon-

14 inside our bodies from birth.


Searching for Invisible rays

• Radiation is everywhere, but can be difficult to detect.

• German Physicist Wilhelm Roentgen (1845-1923)

When he bombarded certain materials with electrons they emitted some sort of energy.

These Rays could darken photographic film..

Roentgen named X rays with an “X” 100 years ago because they were previously unknown.


Searching for invisible Rays

• French Physicist Henri Becquerel (1852-1908)

• Discovered by accident that Uranium salts emitted rays that darkened photographic plates.

• Without Bombardment with electrons!! Weird…..



Searching for Invisible Rays

Marie Curie and her husband Pierre named the energy (invisible rays) radioactivity. Early discoveries of radiation relied on photographic equipment.

Later, more sophisticated devices such as the Geiger-Müller counter were developed to more precisely measure radioactivity.

See pages 288 - 289

Radium salts, after being placed on a photographic plate, leave

behind the dark traces of radiation. Alpha radiation…

The Geiger-Muller Counter

• Detects Alpha Particles, Beta Particles, and Gama Rays. Ionizing Radiation…

• We will talk about this guy later….


Detecting Radiation….

• Radiation includes radio waves, x rays, MICROWAVES etc..

• The Electromagnetic Spectrum


Ionizing: Enough E to remove an electron therefore can alter chemical bonds.

Non-Ionizing: Not enough E to remove an electron but sure can excite one.

Cancer Causing?

The good and Bad

Being exposed to radioactive materials can be beneficial or harmful. X rays, radiation therapy, and electricity generation are beneficial. High-energy particles and waves damage DNA in our cells.


CANDU: Fission to make Electricity.

Questions??

• Why was the discovery that Uranium salts emitted radiation a surprise?

• What did Marie Curie call the Process by which materials give off radiation?


This radiation was due to decay and not because of direct bombardment with electrons.

Radioactivity

Group Project….. You have 30 min…

• Each group will be given a subject:

• You will need to work as a team to create a short presentation for the class on your subject.

• Here are some guiding questions that you may want to talk about.

• What is your topic? Why is it significant to science? Why does it matter to us? How does it work? Does it affect people? Are there more then one application if so what? Are there any dangers relating to your topic? What is interesting about your topic and can you relate to it?


CONSIDERED RESPONSE (MARCH 31)

• What do you think Radon is? Draw a picture of how Radon may get in your house.

• What do you think Ionizing Radiation is? Where would you find such radiation?

• Do you think cell phones are harmful or not harmful to your health? Explain your reasoning.

• What do you know about radioactive tracers? What do you think they are? How would they be used?

• what do you think UV radiation is? Can you list some pros and cons to UV radiation? Why do you think some people think tanning beds are unsafe?


TUESDAY

•TUESDAY


Journal Activity (10min)

• Initial Response

• Describe what radioactive decay means to you.

• Do your best to describe the differences between atomic mass and the mass number.

• What do you think an isotope is?



Atomic Theory Review..

• Atoms are made up of smaller particles called subatomic particles.

• The nucleus is at the centre of an atom. The nucleus is composed of protons and neutrons. Electrons exist in the space surrounding the nucleus. # of protons = # of electrons in every atom Atomic number = # of protons = # of electrons

See page 170

Atomic Theory Continued

•How is the atomic mass calculated?


Atomic #

Atomic Mass

Average of the total mass of Protons, neutrons and electrons that make up an atom.


Isotopes and Mass Number

• Isotopes are different atoms of the same element, with the difference between the two atoms being the number of neutrons in the nucleus. Isotopes have the same number of protons and therefore the same atomic

number as each other. By having different numbers of neutrons, isotopes have different mass

numbers.

See page 289 - 290

Iso 1

Iso 2

• Remember at the start of the semester we looked at Isotopes?


Isotopes of Iron


Each Isotope is written with its atomic number and its mass number..

Atomic Number

Mass Number

Atomic numbers and Mass Numbers???

• So what’s the different between an elements Atomic Number and its Mass number? Ideas?


Atomic #

Atomic #

Atomic Mass

Mass #

WHY OH WHY DO THEY WRITE IT DIFFERENT?

Isotope (atomic) Notation Periodic Table Notation

- Mass number= Total protons and neutrons found in a specific isotope (Top Left)

-Atomic Mass = Average Total (all isotopes) Protons + Neutrons+ Electrons (bottom Left)

-Atomic # = Number of Protons (Bottom Left) -Atomic #=Number of Protons (Top Left)



Representing Isotopes

• Isotopes are written using standard atomic notation. Chemical symbol + atomic number + mass number. Potassium has three isotopes,

See page 290

1939 K, 19

40 K, 1941K

Atomic Mass Explained

• ( % Mass # % Mass# % Mass #) 3

• Atomic Mass 39.1


1939 K, 19

40 K, 1941K

Potassium is found in nature in a certain ratio of 3 isotopes.93.2% is potassium-39, 1.0% is potassium-40, and 6.7% is potassium-41

Atomic mass = (0.932 x 39) + (0.001 x 40) + (0.067 x 41) = 39.1

Questions:

• What is an isotope?

• What do all isotopes have in common?

• How are isotopes different?

• What info is given about the nucleus of an isotope by its mass number?


Different atoms of an element, same # protons, diff # neutron

Sum of an atoms protons and neutrons

same # protons

Different # of neutrons

Questions…

• Fill in the Blanks…


10 11 21

14 16 303 4 7

27Aluminum-27

6Lithium-6

Questions


35

46

Bromine-81

Questions


17

Chlorine-37

Questions


16

33

Sulfur -33

Radioactive Decay

• Unlike all previously discovered chemical reactions, radioactivity sometimes results in the formation of completely new atoms.


Previously A + B AB

Radioactivity F D

Radioactive Decay

Radioactivity results from having an unstable nucleus. When these nuclei lose energy and break apart, decay occurs.

Radioactive decay releases energy from the nucleus as radiation. Radioactive atoms release energy until they become stable, often as different

atoms.


Unstable Nucleus.. stable Nucleus..


Radioactive Decay

An element may have only certain isotopes that are radioactive.• These are called radioisotopes.

See page 293Radioisotope uranium-238 decays in several

stages until it finally becomes lead-206.

Journal Activity (10min)

• Considered Response

• Describe what radioactive decay means to you.

• Do your best to describe the differences between atomic mass and the mass number.

• What do you think an isotope is?


WEDNESDAY

•WEDNESDAY


INITIAL/considered RESPONSE..

• Bohr models… what are they?

• When creating a Bohr model of 2 isotopes of Potassium what differences would you see?

• Draw a Bohr model of Neon 21 and Neon 22?


•THURSDAY


Initial Response

• Knowing what you know about radiation what do you think are the differences between three types, alpha, beta, and gamma radiation?

• Draw three pictures of what you think is happening to the atom in each case.

• Write what you think the symbols are for alpha beta and gamma.



Three Types of Radiation

• Rutherford identified three types of radiation using an electric field. Positive alpha particles were attracted to the negative plate. Negative beta particles were attracted to the positive plate. Neutral gamma rays did not move towards any plate.

See page 294

Alpha Particles

• Alpha radiation is a stream of alpha particles. They are positively charged, and are the most massive

of the radiation types. Alpha particles are essentially the same as helium

atoms. Alpha particles are represented by the symbols


24 or 2

4 He

Alpha Particles

Because it has two protons, it has a charge of 2+. Alpha particles are composed of 2 Protons and 2

Neutrons. The release of alpha particles is called alpha decay.



Three Types of Radiation (continued) :Alpha Radiation

Alpha particles are slow and penetrate materials much less than the other forms of radiation. A sheet of paper will stop an alpha particle.

See page 294 - 295Radium-226 releases an alpha particle and becomes Radon-222. Radon has two less protons than radium.

Questions: Alpha


Beta Radiation

• A beta particle is an electron and is negatively charged. Beta particles are represented by the symbols .

Electrons are very tiny, so beta particles are assigned a mass of 0.

Since there is only an electron, a beta particle has a charge of 1–.


Beta Radiation

Beta decay occurs when a neutron changes into a proton + an electron. The proton stays in the nucleus, and the electron is released.


-10 or -1

0e


Three Types of Radiation (continued) :Beta Radiation

It takes a thin sheet of aluminum foil to stop a beta particle.

See page 296Iodine-131 releases a beta particle and becomes xenon-131. A neutron has turned into a proton and the released electron.

53131I 54

131 Xe + –10

or

53131I 54

131 Xe + –10e

Questions: Beta


Three Types of Radiation (continued) :Gamma Radiation

• Gamma radiation is a ray of high-energy, short-wavelength radiation. Gamma radiation has no charge and no mass, and is represented

by the symbol Gamma radiation is the highest-energy form of electromagnetic radiation.


00

2 gamma rays

It takes thick blocks of lead or concrete to stop gamma rays. Gamma decay results from energy being released from a high-

energy nucleus.



Three Types of Radiation (continued) :Gamma Radiation

Often, other kinds of radioactive decay will also release gamma radiation. Uranium-238 decays into an alpha particle and also releases gamma rays.

See page 297

2860 Ni* 28

60 Ni + 00

92238 U 90

234 Th + 24 He + 2

Questions : Gama



Radiation and Radioactive Decay Summaries, and Nuclear Equations for Radioactive Decay

• Nuclear equations are written like chemical equations, but represent changes in the nucleus of atoms. Chemical equations represent changes in the position of atoms,

not changes to the atoms themselves. In Nuclear Equations

1. The sum of the mass numbers does not change.2. The sum of the charges in the nucleus does not change.

3. VIDEO

Summary


Considered Response

• Knowing what you know about radiation what do you think are the differences between three types, alpha, beta, and gamma radiation?

• Draw three pictures of what you think is happening to the atom in each case.

• Write what you think the symbols are for alpha beta and gamma.


•END OF 7.1


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MONDAY (c) McGraw Hill Ryerson 2007. JOURNAL PROJECT YOUR JOURNAL WILL BE WORTH ___% OF THIS CHAPTERS GRADE EACH DAY YOU WILL BE REQUIRED TO ANSWER THE