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Friday 2/26/10. In-Class Post-lab Introduction to Radioactivity HW Review Constant review of USA vs. Finland At-Home Moodle quiz Complete Lab Analysis Questions Week 8 BLOG Learning Goals Get with the PROGRAM!. Post-Lab Discussion. Pre-Lab

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Friday 2/26/10

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Friday 2 26 10

Friday 2/26/10

  • In-Class

    • Post-lab

    • Introduction to Radioactivity

    • HW Review

    • Constant review of USA vs. Finland

  • At-Home

    • Moodle quiz

    • Complete Lab Analysis Questions

    • Week 8 BLOG

  • Learning Goals

    • Get with the PROGRAM!


Post lab discussion

Post-Lab Discussion

  • Pre-Lab

    • Chemical equations are balanced b/c of the Law of Conservation of Matter

    • The reactants react and form the products….

      • Reactants on the left

      • Products on the right

    • The gas collected is carbon dioxide

  • The Lab

    • The threshold level is the amount that occurs which causes another event to happen


Post lab more

Post-Lab (more)

  • The Lab

    • Purpose….

      • A volcano will erupt when gases build up to a certain point. The prediction of an eruption is based on the level of gases.

      • Different volcanic types will erupt when different gases reach a certain threshold.

      • More accurate than earthquake predictions but still not 100% accurate.


Introduction to radioactivity

Introduction to Radioactivity

Learning Goal: Students will be able to…

- explain what isotopes are.

- use correct symbol notation to express different isotopes of an element.

- explain what it means for a substance to be radioactive.

- describe the 3 different types of radiation.


Atomic structure

Atomic Structure

What are the different subatomic particles?

Where is each one located in an atom?

Which type of particle is the most ‘important’ in determining the type of element it is?


Isotopes

Isotopes

Isotopes are atoms of the same element that contain different numbers of neutrons.

For example, atoms of Carbon-12 and Carbon-13 each contain 6 protons in their nuclei, but an atom of Carbon-12 has 6 neutrons while Carbon-13 has 7 neutrons.


2 he 4 0026

Isotopes

Atomic Number

(# of Protons)

2

He

4.0026

Atomic Mass

(Weighted Avg. of Masses of All Naturally-Occurring Isotopes of the Element)


Isotopes1

Isotopes

We specify which isotope of an element we’re talking about by either naming it, or with a symbol.

Example: The symbol for the Boron-11 isotope is

Which means that there are 5 protons and 6 neutrons in an atom of Boron-11.

11

B

5


Isotope practice

Isotope Practice

13

Carbon-14

N

7

Determine the number of protons and neutrons in each of the following isotopes. (You may need a periodic table.)

22

Na

Oxygen-18

11


Isotope practice1

Isotope Practice

13

7 Protons

6 Neutrons

Carbon-14

N

7

6 Protons, 8 Neutrons

Determine the number of protons and neutrons in each of the following isotopes. (You may need a periodic table.)

22

11 Protons

11 Neutrons

Na

Oxygen-18

11

8 Protons, 10 Neutrons


Radioactivity

Radioactivity

Radioactivity is the process whereby certain isotopes emit particular forms of radiation.

(This radiation isn’t necessarily the same as electromagnetic radiation, though.)

Any substance that emits these forms of radiation is said to be radioactive.


Radioactivity1

Radioactivity

There are 3 major forms of emitted radiation, known as alpha, beta, and gamma radiation.

Types of radiation were originally categorized based on their penetrating power, which is related to the energy they carry.

Today we understand more about what exactly is being emitted in each type of radiation.


Radioactivity2

Radioactivity

Alpha Particles - barely energetic enough to penetrate a piece of paper, an alpha particle consists of 2 protons and 2 neutrons (basically a Helium nucleus)

Beta Particles - can pass through 3mm of aluminum, a beta particle is just an electron emitted from the nucleus

Gamma Rays - very energetic, can pass through several centimeters of lead, a gamma ray is a very high-frequency electromagnetic wave


Sources of radioactivity

Sources of Radioactivity

Many naturally-occurring isotopes are radioactive, and so are some man-made substances.

Coal power plants release more total tons of radioactive isotopes into the air each year than nuclear power plants produce. (And the nuclear waste is contained, not released into the environment.)


Sources of radioactivity1

Sources of Radioactivity

The Earth’s interior is hot because of energy released from radioactive isotopes inside the Earth.


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