Radioactive

RadioactiveRadioactiveRadioactiveRadioactiveDennis Christian

Amirulhakim HanifDennis Christian

Amirulhakim Hanif

Basic ConceptInside an atom there are three kinds of particleprotonsneutronelectron

The nucleus contains protons and neutrons

The region beyond the nucleus contains electrons that balance out the charge of the protons

There are roughly as many protons as neutrons

Because like charges repel each other,there is always a force trying to push the protons apart

Provided there are not too many protons in the nucleus, other forces can hold the protons together

If the ratio of protons to neutrons is not within certain limits,protons may not be held firmly together,and they form an unstable nucleus.This is what makes isotopes of some elements radioactive.

Example

Carbon,the element found in all living things has the symbol C

The normal form (isotope) has an atomic weigh of 12 and is written as carbon-12, but the radioactive(isotope)version has two extra neutrons, so the symbol is carbon-14

Alpha Particle

The nucleus breaks down

A stable combination of two protons and two neutrons (alpha particle) is ejected from the nucleus as it decays

An alpha particle is also the nucleus of the atom of helium

If it captures two electrons, it becomes a natural helium atom

It does this by crashing into nearby atoms

All alpha particles readily transform into helium atoms

Beta Particle

The nucleus breaks down and eject an electron(beta particle)

What remains is a new element with a higher atomic number

This commonly happens in light elements

For example

Tritium(an isotope of hydrogen) breaks down into helium

Carbon changes to nitrogen

Nitrogen changes into oxygen

Gamma Radiation

The nucleus breaks and rearranges itself into a tighter cluster, sending out a wave of energy

The wave of energy is called gamma radiation

It is the same type of radiation as X-rays

Gamma rays caries enough energy to damage cells

This is how they kill living matter

It is for these reasons that radioactive sources should be shielded behind some absorbing material such as lead

Half LifeHalf-life is the period of time taken for the amount of a substance undergoing decay to decrease by half

Half-lives are used to describe quantities undergoing exponential decay

Example, radioactive decay—where the half-life is constant over the whole life of the decay, and is a characteristic unit for the exponential decay equation.

A half-life can also be defined for non-exponential decay processes

Corresponding to sediments in environmental processes, if the half-life is greater than the residence time, then the radioactive nuclide will have enough time to significantly alter the concentration

A half-life describes the decay of discrete entities, such as radioactive atoms

It does not work to use the definition "half-life is the time required for exactly half of the entities to decay"

Example, if there is just one radioactive atom with a half-life of 1 second, there will not be "half of an atom" left after 1 second. There will be either zero atoms left or one atom left, depending on whether or not the atom happens to decay.

An exponential decay process can be described by any of the following three equivalent formulas:

■ N0 is the initial quantity of the substance that will decay (this quantity may be measured in grams, moles, number of atoms, etc.),

■ N(t) is the quantity that still remains and has not yet decayed after a time t,■ t1 / 2 is the half-life of the decaying quantity,■ τ is a positive number called the mean lifetime of the decaying quantity,■ λ is a positive number called the decay constant of the decaying quantity.

• The three parameters t1 / 2, τ, and λ are all directly related in the following way:

• where ln(2) is the natural logarithm of 2 (approximately 0.693)

Half Life

Examples of Radioactive ElementsExamples of Radioactive Elements

Uranium-235

703,800,000 YearsSpecific Activity : 80,011 Bq/g

atom% : 0.72%Weight % : 0.711%Activity % : 2,2%

Activity in 1 g 2nat : 586 bq

Uranium-235

703,800,000 YearsSpecific Activity : 80,011 Bq/g

atom% : 0.72%Weight % : 0.711%Activity % : 2,2%

Activity in 1 g 2nat : 586 bq

Uranium-238

4.468 · 109 yearsSpecific Activity : 12,445 Bq/g

atom% : 99.275%Weight % : 99.284%Activity % : 48.9%

Activity in 1 g 2nat : 12,356 bq

Uranium-238

4.468 · 109 yearsSpecific Activity : 12,445 Bq/g

atom% : 99.275%Weight % : 99.284%Activity % : 48.9%

Activity in 1 g 2nat : 12,356 bq

Americium-241

432,7 Years

Americium-241

432,7 Years

Examples of Radioactive ElementsExamples of Radioactive Elements

Cesium-133

Isotope 133CsNatural abundance : 100Spin (I): 7/2

Frequency relative to 1H = 100(MHz): 13.116207Receptivity, DP, relative to 1H = 1.00 : 0.0484Receptivity, DC, relative to 13C = 1.00 : 276Magnetogyric ratio, γ(107 rad T-1 s-1): 3.5332539Magnetic moment, μ (μN) : 2.9277407 -3.43(10) and 302(21) [Mössbauer state]Line width factor, 1056l (m4) : 0.0000019

Cesium-133

Isotope 133CsNatural abundance : 100Spin (I): 7/2

Frequency relative to 1H = 100(MHz): 13.116207Receptivity, DP, relative to 1H = 1.00 : 0.0484Receptivity, DC, relative to 13C = 1.00 : 276Magnetogyric ratio, γ(107 rad T-1 s-1): 3.5332539Magnetic moment, μ (μN) : 2.9277407 -3.43(10) and 302(21) [Mössbauer state]Line width factor, 1056l (m4) : 0.0000019

Thorium

Name of Element : Thorium Symbol of Element : Th Atomic Number of Thorium : 90Atomic Mass: 232.0381 amuMelting Point: 1750.0 °C - 2023.15 °KBoiling Point: 4790.0 °C - 5063.15 °KNumber of Protons/Electrons in Thorium : 90Number of Neutrons in Thorium : 142Crystal Structure: Cubic Density @ 293 K: 11.72 g/cm3 Color of Thorium : silvery

Thorium

Name of Element : Thorium Symbol of Element : Th Atomic Number of Thorium : 90Atomic Mass: 232.0381 amuMelting Point: 1750.0 °C - 2023.15 °KBoiling Point: 4790.0 °C - 5063.15 °KNumber of Protons/Electrons in Thorium : 90Number of Neutrons in Thorium : 142Crystal Structure: Cubic Density @ 293 K: 11.72 g/cm3 Color of Thorium : silvery

Protactinium

•Symbol: Pa•Atomic number: 91•Atomic weight: 231.03588 (2)•Standard state: solid at 298 K•CAS Registry ID: 7440-13-3•Group in periodic table:•Group name: Actinoid•Period in periodic table: 7 (actinoid)•Block in periodic table: f-block•Colour: silvery metallic•Classification: Metallic

Protactinium

•Symbol: Pa•Atomic number: 91•Atomic weight: 231.03588 (2)•Standard state: solid at 298 K•CAS Registry ID: 7440-13-3•Group in periodic table:•Group name: Actinoid•Period in periodic table: 7 (actinoid)•Block in periodic table: f-block•Colour: silvery metallic•Classification: Metallic

FactsOne ton of natural uranium can produce more than 40 million kilowatt-hours of electricity. This is equivalent to burning 16,000 tons of coal or 80,000 barrels of oil.

One pound of uranium will make a ball only 1.3 inches in diameter. Make an "OK" sign with your forefinger and thumb to see how big that ball would be.

The price of uranium was approximately $10.75 per pound in early 2003. By mid 2006, the price had risen to approximately $45.00 per pound. In early 2007 the price approached $100.00 per pound.

Uranium boils at about 3,818 degrees Celsius

Development of Tiny Thorium Reactors Could Wean the World Off Oil In Just Five Years

One ton of thorium can produce as much energy as 200 tons of uranium and 3.5 million tons of coal

Thorium has huge potential for use as nuclear fuel in breeder reactors, especially since its chief isotope is "breedable" but is not useful for nuclear weapons.

Radioactive Effect on Human

• Nausea

• Vomiting

• Headache

• Some loss of white blood cell

• Losing hair (with radiation exposure >200 rems)

• Kill nerves cell at >5000 rems

• Example: Hiroshima and Nagasaki Bombings

• Chernobyl Accident

• Rem is unit of effective absorbed dose of ionizing radiation in human tissue