Radioactive reactions deal with the chemical instability of the nucleus in an atom.
Heavy (large atomic mass) elements undergo radioactive reactions in order to increase the stability of their nuclei.
Concept #1: Understanding Nuclear Reactions.
In a typical stoichiometric reaction we begin with elements as reactants and end with the same elements in different forms as products.
In a nuclear reaction the number of protons in an element are affected and so the identity of the element changes.
The three most common types of radioactive reactions are alpha decay or capture, beta decay or capture and gamma emission.
Concept #2: Types of Nuclear Reactions.
In a radioactive decay or emission reaction the radioactive particle is ejected from the nucleus and forms a product.
In a radioactive capture or absorption reaction the radioactive particle is taken into the element and so is seen as a reactant.
An alpha particle is comprised of 2 protons and 2 neutrons.
Concept #3: Understanding Alpha Decay or Emission.
An alpha decay or alpha emission occurs when an unstable nucleus ejects an alpha particle to create a new element.
Concept #4: The Alpha Particle.
The alpha particle is one of the largest radioactive particles with the highest ionizing power, but lowest penetrating power.
Example #1: Write balanced nuclear equations for each of the following alpha emissions.
a) Curium (Cm) – 248
b) Bismuth (Bi) – 207
A beta particle has no atomic mass and is represented by an electron.
Concept #5: Understanding Beta Decay or Emission.
A beta decay or beta emission occurs when an unstable nucleus ejects a beta particle to create a new element.
Concept #6: The Beta Particle.
Beta particles are smaller in size, and therefore have more penetrating power. Luckily, they are less radioactively damaging because of their lower ionizing power.
Example #2: Write balanced nuclear equations for each of the following beta emissions.
a) Magnesium (Mg) – 25
b) Ruthenium (Ru) – 102
Example #3: Pb – 208 is formed from Th -232. How many alpha and beta decays have occurred?
A gamma particle has no atomic mass and no atomic number and is represented by the sign gamma.
Concept #7: Understanding Gamma Radiation.
Gamma radiation is involved in the electromagnetic spectrum. Gamma rays possess the highest energy, while radio waves have lowest energy in terms of the spectrum.
Concept #8: The Gamma Particle.
The gamma particle does not create a new element like the other radioactive particles, but instead causes the excitation of electrons within an element.
Gamma Particles have lowest ionizing power, but are the most dangerous because of their highest penetrating power.
Example #4: Which of the following represents an element that has experienced a gamma emission?
Concept #9: Understanding Electron Capture.
In an electron capture or electron absorption reaction our electron particle is a reactant and not a product.
Example #5: Write balanced nuclear equations for each of the following elements after undergoing electron capture.
a) Rutherfordium (Rf) – 263
b) Nobelium (No) – 260
c) Lead (Pb) – 207
A positron particle is referred to as the anti-electron particle because it looks like a positively charged electron.
Concept #10: Understanding Positron Emission.
A positron decay or positron emission occurs when an unstable nucleus ejects a positron particle to create a new element.
Example #6: Write balanced nuclear equations for each of the following positron emissions.
a) Uranium (U) – 235
b) Radon (Rn) – 222
Example #7: A nuclide of Th-225 undergoes 3 alpha decays, 4 beta decays, and a gamma emission. What is the product?