Problem 6 - Chemistry and Chemical Reactivity

Question

Cobalt-60, used as a source of high-energy gamma radiation in medical procedures, is made in a nuclear reactor by neutron irradiation of cobalt-59. Write an equation for this reaction.

Step-by-Step Solution

Answer

Co-59 + n → Co-60.

Step 1: Identify the Isotopes Involved

Start by identifying the known isotopes involved in the reaction. Cobalt-59 (Co-59) is the starting isotope that undergoes neutron irradiation. This process will lead to the formation of cobalt-60 (Co-60).

Step 2: Understand Neutron Irradiation

In nuclear reactions involving neutron irradiation, a neutron (n) is added to a nucleus, resulting in the formation of a new isotope. Here, Co-59 absorbs a neutron to become Co-60.

Step 3: Write the Nuclear Reaction Equation

In this nuclear reaction, we begin with Co-59, which has an atomic number of 27. When it absorbs a neutron (1n), it transforms into Co-60. The reaction can be written as: \[ \text{Co-59} + \text{n} \rightarrow \text{Co-60} \] where a single neutron is absorbed.

Key Concepts

Cobalt-60

Cobalt-60 is an important radioactive isotope that has various applications, especially in the medical field. It is produced when Cobalt-59 absorbs a neutron and undergoes a transformation. This process happens in nuclear reactors where the environment is well-suited for neutron bombardment. What makes Cobalt-60 particularly valuable is its ability to emit high-energy gamma rays. These gamma rays are integral in many applications, ranging from sterilizing medical equipment to providing treatment in radiation therapy for cancer patients. When produced, Cobalt-60 has an atomic number of 27, which is the same as Cobalt-59. However, it has a higher mass number of 60 due to the addition of a neutron. This change does not alter its chemical properties significantly, but it endows the isotope with radioactive properties.

Neutron Irradiation

Neutron irradiation is a critical process used in various nuclear reactions to create new isotopes. This method involves exposing a target nucleus, such as Cobalt-59, to a stream of neutrons. When a neutron is captured by the target nucleus, the result is an isotope with an increased mass number. The atomic number remains constant because neutrons do not have a charge; they do not affect the number of protons. For Cobalt-59, capturing one neutron transforms it into Cobalt-60. The equation \[ \text{Co-59} + \text{n} \rightarrow \text{Co-60} \] illustrates this simple yet crucial interaction that alters the mass of the nucleus and imparts radioactivity. Neutron irradiation not only produces valuable isotopes like Cobalt-60 but is also widely used in material analysis and treatment processes.

Medical Applications

Cobalt-60 has found notable application in the field of medicine due to its radioactive properties and ability to emit gamma radiation. One of the primary uses of Cobalt-60 is in the treatment of cancer through a process called radiotherapy. Here, the gamma rays emitted by the isotope are directed towards cancerous cells. These rays help in damaging the DNA of the cancer cells, which effectively slows down or stops their growth. Other medical uses include:

• Sterilization of medical instruments, ensuring they are free from bacteria and pathogens before use.
• Diagnosis and imaging, where gamma rays can help in observing certain tissues or organs.

The precision and effectiveness offered by Cobalt-60 make it an indispensable tool in modern medical treatments, improving the efficacy and safety of various healthcare procedures.