Nuclear Chemistry

Radioactive DecaySpontaneous breakdown of an atom’s nucleus

Breakdown results in a lighter nucleus

Emits electromagnetic radiationNuclear radiation—radiation emitted from nucleus

Radioactive nuclide– nucleus that goes through radioactive decay, unstable. (Ex. Uranium

Types of Radioactive Decay1) Alpha particle (α)

Consists of 2 protons, 2 neutrons emitted during decay Helium nucleus ( 2

4He )—how particle represented

Can be stopped by paper, low energy Atomic number goes down 2, atomic mass goes down 4. Equation: 84

210 Po 82206 Pb + 2

4 He

2) Beta particle (β) Electron given off during radioactive decay Can be stopped by lead or glass Increase in atomic # Equation: 6

14 C 714 N + -1

0 β

3) Gamma Rays Has the most energy, only stopped by lead Ex. X-Rays

Example 1: Nuclear equation when an alpha particle emitted by 210

84Po

Example 2:Nuclear equation when a beta particle emitted by 210

82Pb

Practice: Alpha Decay

1) Be-9

2) U-238

3) Eu-154

Beta Decay

4) Th-234

5) K-43

Half-Life

Time period required for half of a radioactive nuclide to decay.

Vary depending on the nuclide, unique for each nuclide.

Ex. 146C has a half-life of 5715. Therefore, if we

have 10g of 146C, in 5715 years we will have 5g.

Half-Life Equation

AE = AO * 0.5 t/t(1/2)

AE = Substance amount

A0 = Initial substance amount

t = time elapsed

t1/2 = half-life

Example 1: Plutonium-239 has a half life of 24,110 years. We have 100g of this substance. How many grams will we have after 96,440 years?

More on Nuclear Chemistry

Nuclear Fission

Nuclear reaction where nuclei are SPLIT

Nucleus is broken down into a more stable nucleus.

HUGE amount of energy is released

Critical mass = minimum number of nuclei that can provide enough neutrons to maintain chain reaction.

Nuclear reactors = controlled fission reactions.

**Can induce a nuclear chain reaction!!!

Nuclear Reactors

Location where controlled fission reactions occur

Fuel rods in the core contain enriched uranium

Steam generation steam turbine electric generator

Control rods take in neutrons so fission is controlled

Production of radioactive waste

A TON of water is used to cool the reactors

Nuclear FusionNuclei having a light mass are joined.

Combination of light nucleiCreates heavy nucleus

Results in larger, stable nucleus.

MORE energy released than in nuclear fission !!!

Hard to control

Initiated by fission reaction (fission bomb) ---- H bomb

**Type of reaction happening in the sun and stars.

-fuel: hydrogen atom

cu

Applications to Nuclear Radiation

1) Radioactive DatingAge determination of artifact based on presence of

radioactive nuclide

2) Medical PurposesCancer treatmentsRadioactive tracers

3) Food ProcessingMeat exposed to radiationKills microorganisms

Prompt

We talked about nuclear energy today. Do you support or disagree with this type of green energy? Support your answer.

How could we harness the nuclear energy in the sun? Discuss how we might use nuclear fusion to benefit us.