Do NowWork silently. Raise hand to ask Ms.

Hughes anything.

1. What is the lewis dot structure for O?

2. For C?3. For Li?4. For Ne?5. For F?

Announcements

• Unit 3 test this Friday

• If you have not taken 2 chemistry tests yet this semester, see me after to arrange a make up

• Also, come in for quick tutoring, then RETAKE GLEs for a GRADE BOOST

Mystery Element•When it reacts with Oxygen it is called rust.

•Last year a movie came out called _ _ _ _man.

•If you don’t have enough of this, you may have anemia.

Objectives• SWBAT identify radioactive

particles

• SWBAT explain uses of radiation in everyday life

Nuclear Chemistry

It’s not just the

mushroom cloud in the

sky!

Examples of Nuclear Chemistry?

Examples of Nuclear Chemistry

• Sun• Nuclear/atomic bomb• Chemotherapy• Nuclear power plants• Television• X-Rays• Cosmic Rays

Nuclear Chemistry

• Which part of the atom does nuclear chemistry have to do with?– THE NUCLEUS!!

• This area of chemistry is new and cutting edge– New ideas about and uses for

radioactivity being found every day.

The Nucleus• Which subatomic particles are in the nucleus?

• What charges do they have?

• Opposites attract, what do sames do?

• So how are all the protons kept so close in the nucleus?

The Nucleus• Which subatomic particles are in the nucleus?

– Protons and neutrons• What charges do they have?

– Protons are positive, neutrons are negative• Opposites attract, what do sames do?

– Sames repel each other• So how are all the protons kept so close in the

nucleus?– It takes a lot of ENERGY!!!!

Radioactivity and Radiation

• Radioactivity is the spontaneous (random) disintegration (falling apart) of the nucleus.

• Radiation is energy emitted from a radioactive source– It can knock electrons out of atoms!!!

Harmful Effects

• Exposure to radiation can cause hurt living things– The emitted energy can rip off electrons

on the atoms in your DNA– These atoms will start reacting with the

rest of your DNA• Which will destroy it or mutate your DNA

Radiation Therapy

• Cancer Patients often use radiation to kill the cancer cells in their body– A pill of radioactive material is inserted

near the tumor– The pill emits radiation which kills the

cancer cells

• Why do cancer patients on radiation look so sick?

Radioactive Dating

• The approximate age of an object can be determined based on the amount of radioactive atoms in the object

– Carbon dating is used to determine how old ancient objects are• Like mummies, clothes, and bones.

– Why do you think some people might not like the idea of radioactive dating?

*We’ll learn more about this later

Food Irradiation• Some food is intentionally exposed to radiation

to make it safer to eat– Like beef and chicken– You also don’t have to refrigerate the food!– It is approved by the FDA as safe

• What might you be trying to kill on the meat?• Why should food irradiation be used?• Why do you think food irradiation is not

popular yet?

Radioactive Tracers

• Radioactive atoms can be used to replace other atoms in normal objects– Scientist learn how our body works at the

molecular level with tracers– Cancer in bones is discovered using tracers

since x-rays can’t go through bones– What other items might be helpful to tag?

Nuclear Weapons

• Nuclear Weapons take advantage of all the energy in the nucleus– they let a chain reaction occur and this

creates the giant explosion!

• Should the United States get rid of its nuclear weapons?

Nuclear Power Plants

• Nuclear Power plants also use all the energy stored in the nucleus of the atom– Scientists control the reaction and prevent the

explosion– Nuclear Power plants are a much cleaner

source of energy than fossil fuels• They do not contribute to the greenhouse effect

• Why do we not use more nuclear power plants?

Nuclear Waste

• Although Nuclear Power Plants do not pollute the skies, they do create radioactive waste

– The Nuclear waste can be dangerous to any living thing that is near it

• Where should we put the radioactive waste?

Examples of Radioactive Elements

• Uranium• Polonium• Astatine• Radon• Francium

• Radium• Actinium• Thorium• Proactinium• All other man-

made elements heavier than Uranium

Three Types of radiation:

•Alpha ()•Beta ()•Gamma ()

Alpha Particle2 protons and 2

neutrons

He2

4or

2

4

He2

4Atomic Mass (protons + neutrons)

Atomic Number

(protons)

Beta Particlea stream of highspeed electrons

e

or

10

Gamma Rayvery energetic form

of light (a ray, not a

particle)

Level of Penetration

Symbol Charge Positive Negative None

Size largest Very small smallest

Penetration power

Low, skin stops it

Medium, wood stops it

High, concrete stops it

He2

4

e

Remember the Cathode Ray Tube???

Alpha Decay• Problem: Nucleus is too heavy• Solution: Nucleus emits an alpha

particle• What else comes out?

• Must balance the equation• Top numbers on each side must be equal• Bottom numbers on each side must be

equal

HePbPo 42

20682

21084

Beta Decay

• The Problem: too many neutrons or too few protons

• The Solution: An electron is pulled off a neutron, which turns into a proton– The emitted particle is called a beta

particle– Mass stays the same!!!

01147

146 NC

Gamma Decay

• The Problem: too much energy• The Solution: The nucleus releases

energy in the form of high-energy gamma particle– Often accompanies the other types of

decay– No change in mass or atomic

number!!!00

42

42 HeHe

Balancing Think Aloud

• In the equation below, the species represented by Q is:

AtHeQ 21685

42

Balancing Popcorn

• In the equation below, what fills the blank?

___5626

26094 FePu

Uses of radiation

• Read the article• Answer questions on separate

sheet of paper

Exit Slip

1. Which radioactive particle is negative?2. Which radioactive particle can

penetrate the furthest?3. Which radioactive particle is most

massive?• Hw:

– Create a graphic organizer of the 3 types of radioactive particles and the uses of radiation to use to study (example: venn diagram, table, etc.)

• Top ten: how’d we do?