Chemistry II Chapter 8: Nuclear Chemistry

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Chemical Reactions occur between what
Different atoms
Nuclear reactions occur between what
Within one atom
Reactions effect on atoms in chemical reactions
Rearranged with other atoms
Reactions effect on atoms in nuclear reactions
Atom is converted into an atom of another element
Valence electrons
Only involved in chemical reactions
Nucleus
Change in nucleus involving protons and neutrons
Chemical reaction energy changes
Realtively small
Nuclear reactions energy change
Big
Chemical reactions are influenced by what?
Temperature
Pressure
Concentration
Nuclear. Reactions are influenced by what?
Nothing. Cannot be altered
Radioactive Decay
Nucleus of an atom decays spontaneously

Gives of particles of rays

Nuclear bombardment
Small particles bombard an atoms nucleus

Man made

Transmutation
Conversion of an atom of one element into an atom of a different element
Types of radioactive decay
Alpha particles symbol
4
He
2
Alpha particle charge
+2
Alpha particle penetrating power
Low
Alpha particle shielding needed
Paper, clothing
Alpha particle emission
Loss of a helium nucleus
Beta particle symbol
e-

B
-1

Beta particle charge
-1
Beta particle penetrating power
Moderate
Beta particle shielding
Metal foil
Beta emission
Neutron splits into a proton and electron which is spit out as a b particle
Gamma ray radiation symbol
Y
Gamma ray charge
Gamma ray penetrating power
High
Gamma ray shielding
5-6 cm lead
1-2 cm concrete
Positron particle symbol
B+
Position particle def
A positive election emitted from the nucleus
Positron charge
Positron emission
A proton kicks out a positive charge to become a neutron

The positron collides with an electron annihilating both and generating energy

Isotopes
Atoms of the same element with different numbers of neutrons
Radioisotopes
Isotopes of atoms with unstable nuclei
What causes unstable nuclei
Too many on too few neutrons in the nucleus

Emit radiation to attain a more stable atomic configurations

Half-life
Is the time required for half of a radioisotope’s bucleinto decay into its products
Half-life formula
Final mass= (initial mass) * (.5)^(time passed)/(half-life value)
Nuclear bombardment types
Fission
Fusion
Fission
The splitting of a large atom into two equal medium sized atoms

Accomplished through nuclear bombardment

Fusion
Combing two small atoms into one slightly larger atom through a collision of their nuclei
Transuranium elements
Are formed in particle accelerators by bombardment of small nuclei into large atoms
Fission cabin reaction
Splitting continues
Energy is released
Controlled chained reaction
Energy released slowly
Uncontrolled chain reaction
Large release of energy
How to control chain reactions
Reduce neutrons speed
Absorb extra neutrons
Nuclear reactor control rods
Absorb neutrons to control fission when lowered
Controlling fusion
Very hard
Much more energy released
Categories: Nuclear Chemistry