Problem 52 - Chemistry and Chemical Reactivity

Question

To synthesize the heavier transuranium elements, a nucleus must be bombarded with a relatively large particle. If you know the products are californium- 246 and four neutrons, with what particle would you bombard uranium- 238 atoms?

Step-by-Step Solution

Answer

Carbon-12 particle is used.

Step 1: Understanding the Problem

We need to find out which particle is used to bombard uranium-238 to produce californium-246 and four neutrons. The equation should conserve both atomic and mass numbers.

Step 2: Write the Nuclear Reaction Equation

Let's represent the unknown particle with variable 'X'. The nuclear reaction can be written as:\[ ^{238}_{92}U + X \rightarrow \, ^{246}_{98}Cf + 4^1_0n \]

Step 3: Determine the Property of Californium

Californium-246 has an atomic number of 98 and a mass number of 246. This provides necessary information for balancing the nuclear equation.

Step 4: Balancing Mass Numbers

The mass numbers (top numbers) in the equation must be balanced. Thus, for the left side:\[ 238 + A = 246 + 4 \times 1 \]\[ 238 + A = 250 \]Solving for \(A\):\[ A = 250 - 238 = 12 \]

Step 5: Balancing Atomic Numbers

The atomic numbers (bottom numbers) must also be balanced. For the equation:\[ 92 + Z = 98 + 0 \times 4 \]\[ 92 + Z = 98 \]Solving for \(Z\):\[ Z = 98 - 92 = 6 \]

Step 6: Identifying the Particle

The particle with mass number 12 and atomic number 6 is carbon-12. Thus, a carbon-12 particle is used to bombard uranium-238.

Key Concepts

Transuranium Elements

Transuranium elements are those elements in the periodic table that have atomic numbers greater than uranium (92). Essentially, these elements do not occur naturally and must be synthesized through nuclear reactions. Understanding their synthesis is crucial in nuclear chemistry.

• Transuranium elements include well-known elements such as neptunium, plutonium, and californium.
• These elements are usually produced in nuclear reactors or particle accelerators by bombarding lighter element nuclei with neutrons or other particles.

Since these elements are not found in nature, their discovery and creation rely significantly on advanced nuclear techniques. The ability to synthesize them opens a field for scientific research, providing critical insights into the nuclear properties of new elements.

Nuclear Bombardment

Nuclear bombardment involves accelerating particles to high velocities to collide with atomic nuclei. This process is integral to creating new elements, especially transuranium elements. By bombarding a nucleus, a new element can be synthesized through fusion of the incoming particle with the pre-existing atomic nucleus.

• The particle often used for bombardment varies depending on the desired reaction outcome.
• This technique allows scientists to extend the periodic table by artificially creating elements beyond uranium.

In our specific exercise, a carbon-12 nucleus was used to bombard a uranium-238 nucleus, a method used to synthesize the heavier nucleus of californium-246. This process demonstrates how nuclear bombardment can alter an element's structure, expanding our understanding of nuclear physics.

Mass Number Conservation

Conservation of mass number is a fundamental principle in nuclear reactions. It dictates that the total mass number before and after a nuclear reaction must remain unchanged. This principle ensures that the number of protons and neutrons remains balanced during any nuclear transformation.

• In nuclear equations, the sum of mass numbers of reactants equals the sum of mass numbers of products.
• This serves as a method to verify the correctness of any nuclear reaction equation.

In the solved exercise, the equation given had a total mass number of 250 on both sides, confirming the conservation of mass number: \[ 238 + 12 = 246 + (4 \times 1) \]Therefore, ensuring that reactions adhere to this principle is crucial for accurately predicting the outcomes of nuclear activities.

Atomic Number Conservation

The principle of atomic number conservation is essential in balancing nuclear equations. It states that the total atomic number must be the same on both sides of the equation.

• The atomic number represents the identity of an element, defined by its protons.
• Balancing these numbers ensures the stability and correctness of nuclear reactions.

For example, in the previous nuclear reaction, the atomic numbers were balanced at 98, with uranium's atomic number (92) combined with the bombarding carbon atom's number (6).The equation: \[ 92 + 6 = 98 + (0 \times 4) \] shows that this conservation was achieved.Understanding this concept is crucial for predicting the products of nuclear reactions and maintaining structural integrity according to nuclear laws.