Nuclear Chemistry
Types of Radiation
Decay Equations
What is radiation?
• Energy traveling through medium with enough
energy to ionize atoms
• Ionize – cause to form an ion
• occurs when an electron is stripped (or "knocked
out") from an electron shell, which leaves the
atom with a net positive charge
What is radioactive decay?
• Process where the nucleus of an unstable atom
loses energy by emitting ionizing particles and
emits radiation
What is transmutation?
• Process in which an atom, called the parent
radionuclide, transforms into:
– an atom with a nucleus in a different state
– an atom with different nucleus containing different
numbers of nucleons
• Either of these products is named the daughter
nuclide.
• The decay process results in nuclear
transmutation(creation of an atom of a new
element)
Synonyms and Symbols
• Atom in nuclear chemistry is described as a nuclide
– EX. Parent or daughter nuclide
• Nucleus in nuclear chemistry is described as a
nucleon = proton + neutron
Types of Radiation
ALPHA EMISSION
• Radioactive decay process by which a particle with
two neutrons + two protons is ejected from the
nucleus of a radioactive atom.
• The alpha particle is identical to the nucleus of a
helium atom.
Alpha Decay Equation
ALPHA PROTECTION
ALPHA ABSORBED BY PAPER + SKIN.
BETA EMISSION
• type of radioactive decay in which a beta
particle (electron) is emitted from an atom as
nucleus breaks apart
BETA ABSORPTION
BETA STOPPED BY METALLIC FOIL AND WOOD.
BETA DECAY EQUATION
BETA DECAY EQUATION
GAMMA EMISSION
• High energy ionizing radiation that is biologically
hazardous
• Produced from radioisotopes when electrons
transition from excited to ground state
GAMMA EMISSION
VERY
DANGEROUS
VERY
PENETRATING
Radioactive Decay Equations
Parent Material
Daughter product
Radiation Emission
Decay Equations
• Alpha Decay • Beta Decay
• Gamma Decay
• 240 Pu  236 U • +234 4ThHe 234 Pa + 0•e Occurs with others
94
92
90
91
2
-1
What is a Half-Life?
• Time is takes for one half of a sample of radioactive
material to decay over time
• Rate of decay ~ every isotope has its’ own rate of
decay
• SOME ARE SLOW Ex. Uranium 4.5 billion years
• SOME ARE FAST
Ex. Radon
3.8 days
Half-Life Example Problems
• There are 3.29 g of iodine-126 remaining in a sample
originally containing 26.3 g of iodine-126. The half-life
of iodine-126 is 13 days. How old is the sample?
39 days old
• If you started with 32 million radioactive atoms, how
many would you have left after five half-lives?
1 million
• The radioactive radon-222 has a half-life of 3.8 days.
How much of an initial 20.0g sample of radon-222
would remain after 15.2 days?
1.25 g
Fission vs. Fusion