Topic 12

Nuclear Chemistry

• Chemistry

• Nuclear Chemistry

• Obj: SWBAT explain what particles are responsible for radioactivity and how the radioisotopes react.

• Do Now: What do you think are some advantages of using nuclear chemistry?

Stability of Nuclei

• Radioactivity comes from the ratio of neutrons to protons in the nucleus

• Elements with atomic numbers greater than 83 are all radioactive

• Radioisotope = a radioactive

isotope of an element

• Gamma rays have no mass or charge and are similar to x-rays but have more energy

• The different particles will react differently when put in an electric field because of their charge.

Alpha Decay

• Alpha particle is released

• Atomic number (number of protons) decreases by 2

• Number of neutrons decreases by 2

• Mass number decreases by 4

Beta Decay

• Beta particle (electron) is released

• Atomic number (number of protons) increases by one

• Number of neutrons decreases by one

• Mass number stays the same

Positron Emission

• Positron is released (converting a proton to neutron)

• Atomic number (number of protons) decreases by one

• Number of neutrons increases by one

• Mass number stays the same

Nuclear Equations

• Mass and charge must be balanced on both sides

• Sum of mass numbers on left = sum of mass numbers on right

• Sum of atomic numbers on left = sum of atomic numbers on right

• Chemistry

• Nuclear Chemistry

• Obj: SWBAT explain the types of decay different radioisotopes undergo.

• Do Now: Complete the equations

Transmutations

• Transmutation = changing one element to another (changing the number of protons)

– Natural transmutation

• Only one reactant

– Artificial transmutation

• More than one reactant

Fission and Fusion

• Fission = splitting of a

heavy nucleus to produce

lighter nuclei

• Fusion = combining light

nuclei to produce a heavier nucleus

•IN NUCLEAR EQUATIONS MASS IS CONVERTED TO ENERGY!!!!!!!

• Fusion produces more energy than fission

– Sun uses fusion

Fission

Fusion

Half-Life

• Radioactive samples decay at a set rate

• The amount of time needed for half of the sample to decay is the half-life

• Shorter half-life = less stable

• To figure out how much of a substance remains, just take the original mass and divide it by 2 for each half-life it goes through.

Graphing Half-life • On graph pick a point

• Go down to half that value (along y-axis)

• Go right until you hit the curve again

• Horizontal distance is the half-life

Uses of Radioisotopes

• C-14 = dates organic material

• U-238 = dates rocks and geological formations

• P-31 = used in fertilizers

• I-131 = detection and treatment of thyroid disorders

• Co-60 = used to destroy tumors and bacteria

• Cs-137 = used to kill bacteria

• Tc-99 = cancer detection

• Chemistry

• Nuclear Chemistry

• Obj: SWBAT explain different properties of radioactive materials and the chemical process behind them.

• Do Now:

• Tracer = radioisotope used to follow the path of a material in a system

• Radioisotopes used for medicine need to have

SHORT HALF-LIVES AND QUICK ELIMINATION FROM THE BODY

• Radioisotopes can be used to measure thickness of materials

Penetrative Powers of Radiation

• Alpha particles can be blocked by a piece of paper

• Beta particles can be blocked by aluminum foil

• Gamma particles can be blocked by a brick wall

• Gamma > Beta > Alpha

Radiation Risks

• Can cause cancer

• Tend to blow up if not handled properly…

• Chemistry

• Nuclear Chemistry

• Obj: SWBAT deepen their knowledge of nuclear chemistry and better prepare for future examinations.

• Do Now:

• Chemistry

• Nuclear Chemistry

• Obj: SWBAT deepen their knowledge of nuclear chemistry and better prepare for future examinations.

• Do Now: take out work

from yesterday

• HW: 2 WORKSHEETS

• Chemistry

• Nuclear Chemistry

• Aim: How do we review chemistry?

• Obj: SWBAT deepen their knowledge of nuclear chemistry and better prepare for future examinations.

• Do Now:

• Chemistry

• Regents Review

• Aim: How do we review chemistry?

• Obj: SWBAT deepen their knowledge of nuclear chemistry and better prepare for future examinations.

• Do Now: Begin Worksheet

• Chemistry

• Nuclear Chemistry

• Aim: How can we determine if/when nuclear energy is an acceptable form of energy to use?

• Obj: SWBAT deepen their knowledge of nuclear chemistry, create an informed argument based on evidence and research.

• Do Now: What did you do over break?

• HW: RESEARCH