Question

What particle is produced by the decay of thorium-214 to. radium- 210 ?

Short answer

An alpha particle \((^4_2\text{He})\) is produced.

Step-by-step solution

Identify the Decay Process

The decay of thorium-214 to radium-210 involves a change in the mass number from 214 to 210. This indicates a loss of 4 units in mass number, suggesting an alpha decay process.

Understand Alpha Decay

In alpha decay, an alpha particle is emitted. An alpha particle is composed of 2 protons and 2 neutrons, making it a helium nucleus with a mass number of 4, represented by \(^4_2\text{He}\).

Confirm the Atomic Number Changes

Thorium has an atomic number of 90, while radium's atomic number is 88. A decrease of 2 in atomic number and 4 in mass number confirms the emission of an alpha particle \((\alpha,\text{or } ^4_2\text{He})\).

Key concepts

Alpha Decay

Alpha decay is a type of radioactive decay where an unstable nucleus emits an alpha particle. This process is common in heavy elements. An alpha particle consists of 2 protons and 2 neutrons, which forms a helium nucleus, symbolized as \(^4_2\text{He}\). During alpha decay, both the mass number and atomic number of the original element decrease. The mass number decreases by 4, and the atomic number decreases by 2.

Alpha decay occurs because the nucleus of the atom is trying to reach a more stable state. The emitted alpha particle reduces the size and energy of the original nucleus, helping it become more stable. This emission results in the formation of a new element with different properties.

For example, if you start with an element like thorium-214, the emission of an alpha particle results in the creation of radium-210. This transformation demonstrates the alleviation of instability by expelling part of the nuclear content.

Thorium-214

Thorium-214 is a radioactive isotope of thorium. Its atomic number is 90, while its mass number is 214. This isotope undergoes nuclear decay to achieve stability. In particular, thorium-214 undergoes alpha decay, releasing an alpha particle to form radium-210.

The decay of thorium-214

• Leads to a drop in the atomic number from 90 to 88.
• Causes the mass number to decrease from 214 to 210.
• Results in the formation of a new element, radium-210.

Thorium-214 is part of the decay series that originates from uranium-238. Understanding its decay helps explain the transformations that occur in natural radioactive decay series, which are significant in geological and nuclear studies.

Radium-210

Radium-210 is the product of thorium-214 after it undergoes alpha decay. This isotope has an atomic number of 88 and a mass number of 210. It is a less stable form of radium that eventually continues to decay further to achieve stability.

When thorium-214 emits an alpha particle, the mass number reduces by 4, and the atomic number reduces by 2, thereby transmuting it into radium-210.

Radium-210, though a pivotal step in its decay series, is not stable in the long term, as it will undergo further decay processes until reaching a stable isotope, usually lead-206 in its decay chain. Studying this decay provides insights into the behavior and properties of radioactive elements, which is crucial in fields such as nuclear physics and radiometric dating.

• Formed by the decay of thorium-214 through alpha decay.
• Continues undergoing radioactive decay processes.
• Is part of the naturally occurring decay series of heavy elements.