Nuclear Energy Unit One Test – Flashcards

• Located in the nucleus
• Atomic mass of 1
• Positive Charge

• Located in circulation around the nucleus
• Has almost no atomic mass
• Negative Charge

• Located in the nucleus
• Atomic mass of 1
• Nuetral charge (no charge)

Mass of protons and neutrons

Example: 

3 protons

+

7 neutrons

=

Atomic mass of  10

1           <----Atomic Number

H                        <----Symbol

Hydrogen                         <----Name

1.00794   <----Average Atomic Mass

• Different forms of an element
• Different isotopes contain different numbers of neutrons

98.9% * 12 / 100 = 11.868

1.1% * 14 / 100 = .154

11.868 + .154 = 12.022

Average Atomic Mass = 12.022amu

• Radiation made up of particles (matter)
• Alpha and Beta radiation

• Radiation sent out in waves
• Gamma radiation

• Top number: Atomic Mass
• Bottom Number: Atomic Number
• Alpha decay causes atoms to lose 2 neutrons and 2 protons
• Answer:

Pu²⁴⁰ ₉₄ ----α----> U²³⁶₉₂ + He⁴₂

• Beta decay causes neutrons to lose their electron.
• This leaves only the proton
• Atomic Mass doesn't change, but the Atomic number goes up

Answer

Po²⁰⁹₈₄ ---β---> At²⁰⁹₈₅ + β⁰_-1

• No particles are disturbed during gamma ray radiation
• There is only a loss of energy

Answer:

Rn²²²₈₆---γ---> Rn²²²₈₆ + γ ⁰₀

• Amount of time it takes for 50% of a sample to decay into something else
• Once half is gone, the remaining portion is cut by half, and so on
• 1 --> ½ --> ¼ --> etc.

Link to see what half life looks like:

http://www.kgs.ku.edu/Extension/gifs/halflife.gif

When a fast moving neutron hits an atom's nucleus, the nucleus splits and releases 3

neutrons that in turn will hit the nuclei of 3 other atoms

Example Link:

http://www.planetseed.com/files/uploadedimages/Science/Earth_Science/Global_Climate_Change_and_Energy/Related_Articles/nuclear1(2).jpg

• Uranium that is filtered to a specific amount of U-235 , the rare isotope
• Bombs require at least 80% enriched uranium
• Power Plants require 2-3% at most

• Movable
• Absorb neutrons released by fission
• Slow down reaction

• Absorb heat from reaction
• Usually graphite
• Slow down neutrons

• Contain 2.5cm pellets of uranium
• Spent nuclear fuel is a problem because it is still radioactive (emits α, β, and γ radiation)

Some examples:

1. No greenhouse gases
2. Needs very little uranium
3. Large uranium deposits in Canada and Australia
4. A single power plant creates huge amounts of energy

Some Answers:

1. Radioactive Waste
2. Not much uranium in the world
3. Safety risks to the general public:
4. Potential radiation exposure or explosion (melt down) if there is an accident

• Put magnets on either side of the Cathode Ray tube, found that the ray going through the tube was negatively charged (the ray curved towards the positive magnet)
• Came up with the plum pudding / chocolate chip cookie model

Site for Cathode Ray Tube Diagram

http://hep.physics.indiana.edu/~hgevans/classes/graphics/em/crt.gif

• Gold Foil Experiment (Shoots α particles at gold foil.  Most particles go through, some are repelled, others turn completely around)
• Came up with nuclear and proton models of the atom

Gold Foil Experiment Diagram

http://www.rsc.org/chemsoc/timeline/graphic/1911_gfoil_02.jpg

Nuclear Model of the Atom

http://www.faqs.org/docs/qp/images/rfmodel.gif

Proton Model of the Atom

http://www.aplusphysics.com/courses/regents/modern/images/atom_diagram.png

• Didn't do many experiments, but had a problem with Rutherford's nuclear model
• Came up with a solution as to why electrons from nuclear model don't crash into the nucleus: they have a set track!  High energy neutrons are further away from the nucleus, while low energy electrons are close to the nucleus

Solar System Model:

http://wiki.nisk.k12.ny.us/groups/84physicalscience/wiki/4ee4b/images/af20c.gif