SCIENCE, MY

FAVORITE!

Please take out:Your lab notebookIonization Across the NationHW Sheet

Ask your partner:“How are you

planning on studying for our test on

Tuesday/Wednesday?”

Next Class is Review Day, Unit Test on

Tuesday!

WARM-UP

As you move across a row in the Periodic Table for any period, the sizes of the atoms _____________. Knowing that, provide an explanation for the ionization energy trend within a period.

Claim: As you move left to right on the PT, the ionization energy ________________.

Evidence: (Give examples from page three on your homework packets)

Reasoning: WHY?!?! Connect to electronegativity and atomic radii

Increases/decreases

decrease

HW REVIEW1. Check your answers with the answer key with your

lab group

2. Log this on your HW sheet

3. Turn in your HW sheet

4. Start thinking about Nuclear Reactions (the last part of our unit!)

LEARNING TARGETS

NUCLEAR CHEMISTRY

AKA– Why shouldn’t I stand in front of a

microwave for extended periods of time?

URANIUM-238 IS USED IN NUCLEAR REACTORS TO GENERATE ELECTRICITY. IN THE NUCLEAR REACTOR, URANIUM-238 CHANGES TO LEAD-209. How can atoms of uranium-238 change into atoms of lead-209?

The nuclear reaction is initiated by colliding the uranium-238 with . What do you think this symbol () represents?

GROUP PRESENTATIONS 10 MIN… GO!

Your Group Must:1. Create a physical model that demonstrates the nuclear process.

2. Present a working model to the class of how the process works.

Your Whiteboard must answer the following:1. An Analogy of what the process is like.2. What do humans use this for?3. How does this process impact life?4. Provide an equation using elements commonly in this process.

5. (Fission and Fusion) What forms of radiation are released by this process? (Decays) What stops this type of decay?

What group am I?Fusion- Xe, IAlpha Decay- Au, BiBeta Decay-O, HgGamma Rays- Cu, Al

WHAT DOES THIS HAVE TO DO WITH ANYTHING? https://www.youtube.com/watch?v=neMEo8ZrwuI

NUCLEAR NOTES

No longer 1:1 ratio

N= neutrons Z= protons

What do you notice?

What do you think the black regions are?

What do you think the blue regions are?

Notice how elements below 20 the proton to neutron ratio is =1, and after 20 the neutrons are >1. What role do you think the neutrons play?

All elements above 83 are radioactive, what do you think that means?

TYPES OF NUCLEAR REACTIONS- FIRST TYPE

Fusion- one element breaks into twoUranium-235 Barium-141 + Krypton-92 + 3n0

This releases a HUGE amount of energy. This was the fission bomb used in WWII!

Remember to conserve mass!

TYPES OF NUCLEAR REACTIONS- SECOND TYPE

Fusion- Combines two light nuclei into one heavier elementProduces even more energy than fissionThis is what happens in stars

Alpha decay- loss of an alpha particle (a Helium nucleus, )

Beta decay- loss of a beta particle (a high energy electron, )

WANT TO TWIST YOUR BRAIN A LITTLE BIT?

Recall:

Nucleus has all the mass. The mass of an atom is equal to all the protons plus all the neutrons.

Example:

He atom:2 protons + 2 neutrons2(1.00728 amu) + 2(1.00867 amu) = 4.03190BUT THE ATOMIC WEIGHT OF Helium-4= 4.00150!

Why does the mass differ if the atomic mass = # of p+ + # of n0?

EINSTIEN!

Remember E=mc2?? The mass difference is due to the

release of energy! Energy is released upon the

formation of a nucleus, the nucleus is lower in energy than its parts!

SO…

If energy is released to break up the nucleus into its parts, the higher the binding energy the more stable the nuclei (since the nucleus would be more favorable in terms of energy).

NUCLEAR BINDING ENERGY… WHY DO STARS STOP AT IRON?

It is no longer favorable to form atoms!

REST OF CLASS

1. Work on Formation of Elements Worksheet (finishing this is homework)

2. Class discussion—If Time allows

3. Free write is our exit task NOT IN OUR NOTEBOOKS

CLASS DISCUSSION

oWhat does it mean to be radioactive?oWhy are radioactive elements unstable?oIf an element spontaneously undergoes radioactive decay, would you expect to find it in nature? Why or why not?

QUESTIONS? Write them

at the bottom of

the page and circle it

FREE WRITE ON NUCLEAR REACTIONS: Compare and contrast

physical/ chemical/ nuclear reactions.