Nuclear Chemistry

Forms of Energy

• The five main forms of energy are:– Heat– Chemical– Electromagnetic– Nuclear– Mechanical

Isotopes

• An isotope is an atom of the same element (same number of protons) that varies in the number of neutrons.– Most elements have several isotopes– Some are unstable and emit radiation– They vary in the number of neutrons. This

changes their atomic mass.

Isotope Notation

• Oxygen-16 has 8 protons and 8 neutrons• Oxygen-17 has 8 protons and 9 neutrons• Oxygen 18 has 8 protons and 10 neutrons

Nuclear Radiation

Many elements can change through radioactivity.-Radioactive elements have unstable nuclei. -Radioactive elements can decay.

– Emit radiation– Can become a different isotope of the

same element– Can become a different element!

Types of Radiation• Alpha Particle

– Helium nucleus with a + 2 charge– The largest radioactive particle– Don’t penetrate very deep

• Beta Particle– A fast moving electron -1 charge– Can travel through paper, but wood or aluminum

will stop it.• Gamma Particle

– Tiny and too small to measure (like photons)– No charge– Travel through clothes and even walls

www.geology.fau.edu/course_info/fall02/ EVR3019/Nuclear_Waste.ppt

http://www.geology.fau.edu/course_info/fall02/%20EVR3019/Nuclear_Waste.ppt

9

Alpha decay

Alpha particle has a mass of 4. -- 2 protons and 2 neutrons--Mass goes down by 4--Atomic # goes down by 2

10

Beta decay

234Th → 234Pa + e-190 91

beta particle

Beta particle has a tiny mass. -- A neutron is converted to a proton--Mass stays the same--Atomic # goes up by 1

11

Gamma radiation

No change in atomic or mass number

11B 11B + 0 γ5 5 0

boron atom in a high-energy state

Did You Know ?

http://www.ambrosevideo.com/resources/documents/89.jpg

Chemical Reactions Nuclear Reactions

Occur when bonds are broken or formed

Occur when nuclei combine, split, & emit radiation

Involve only valence electrons

Can involve protons, neutrons, & electrons

Associated with small energy changes

Associated with large energy changes

Atoms keeps same identity although they may gain, lose, or share electrons, and form new substances

Atoms of one element are often converted into atoms of another element

Temperature, pressure, concentration, and catalysts affect reaction rates

Temperature, pressure, and catalysts do not normally affect reaction rates

Comparison of Chemical and Nuclear Reactions

Sheet1

Chemical ReactionsNuclear Reactions

Occur when bonds are broken or formedOccur when nuclei combine, split, & emit radiation

Involve only valence electronsCan involve protons, neutrons, & electrons

Associated with small energy changesAssociated with large energy changes

Atoms keeps same identity although they may gain, lose, or share electrons, and form new substancesAtoms of one element are often converted into atoms of another element

Temperature, pressure, concentration, and catalysts affect reaction ratesTemperature, pressure, and catalysts do not normally affect reaction rates

Sheet2

Sheet3

Nuclear Fission• A heavy nucleus splits into more stable

nuclei of intermediate mass.

Comparing Fission and Fusion

http://media-1.web.britannica.com/eb-media/03/72203-035-4D92BDBC.jpg

Nuclear Fission Nuclear Fusion

Nuclear Fission Nuclear Fusion

A heavy atom splits into two or more lighter nuclei

Ex: Atomic Bombs & Nuclear reactors

High temp and pressure are used to combine light atoms to make heavier atoms

Ex: Fuels the sun and stars & Hydrogen Bombs

Release huge

amounts of energy

Produce nuclear waste

Little Boy and Fat Man

Atomic Bombs• Atomic bombs are an

example of Fission Reactions.

• “Little boy” and “Fat man” were Atomic bombs made from fission reactions with uranium and plutonium respectively.

• A fission chain reaction is started and continues until the bomb destroys itself.

Nuclear Fusion• Low-mass nuclei combine to form a heavier, more

stable nucleus.

Hydrogen Bombs

• Hydrogen bombs are an example of nuclear fusion.

• Two isotopes of hydrogen, 2H and 3H, fuse together and produce a lot of energy in the process.

• H-bombs release significantly more energy than atomic bombs.

Nuclear Power Plants

map: Nuclear Energy Institute

Nuclear Power Plants• Uranium-235 undergoes nuclear fission and

releases thermal (heat) energy. • This turns water to steam which spins turbines.• The turbines produce electrical energy.

• Nuclear waste is fuel rods with unreacted uranium and radioactive products of fission.

http://images4.wikia.nocookie.net/__cb20060611033960/schools/images/0/0b/Chart.JPG

• The time needed for one-half of the nuclei in a radioisotope to decay and emit their radiation to form a different isotope

• Half-time emitted • Uranium 235 710 million yrs alpha, gamma• Plutonium 239 24.000 yrs alpha, gamma

• During operation, nuclear power plants produce radioactive wastes, including some that remain dangerous for tens of thousands of years

Half-Life

www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

http://www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Relative Doses from

Radiation Sources

cstl-cst.semo.edu/bornstein/BS105/ Energy%20Use%20-%203.ppt

• Genetic damages: from mutations that alter genes

• Genetic defects can become apparent in the next generation

• Cellular damages: to tissue, such as burns, miscarriages & cancers

Effects of Radiation

www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

http://www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

Nuclear ChemistryForms of EnergyIsotopesIsotope NotationNuclear RadiationTypes of RadiationSlide Number 7Slide Number 8Alpha decayBeta decayGamma radiationDid You Know ?Comparison of Chemical and Nuclear ReactionsNuclear FissionComparing Fission and FusionSlide Number 16Slide Number 17Little Boy and Fat ManAtomic BombsNuclear FusionHydrogen BombsNuclear Power PlantsNuclear Power PlantsSlide Number 24Slide Number 25Slide Number 26Slide Number 27Slide Number 28