Question

During a K-electron capture (a) X-rays are emitted (b) neutrous are emitted (c) \(\alpha\) particles are emitted (d) \(\gamma\) rays are emitted

Short answer

(a) X-rays are emitted.

Step-by-step solution

Understanding K-electron capture

K-electron capture, also known as K-capture, occurs when an electron from the innermost shell (the K-shell) of an atom is captured by the nucleus of the same atom. This process changes a proton into a neutron and typically results in a decrease of one in the atomic number of the atom.

Analyzing Emission Types

When K-electron capture occurs, the nucleus absorbs an electron and changes a proton into a neutron. This does not directly emit neutrons, alpha particles, or gamma rays. However, the electron capture process generally results in an excited nucleus, which can then de-excite by emitting a gamma ray.

Addressing the Electron Shell Vacancy

The captured K-shell electron leaves a vacancy in the innermost electron shell. Electrons from higher energy levels drop down to fill this vacancy, and during this transition, characteristic X-rays are emitted. This X-ray emission is typical of electron capture processes.

Comparing Options to the Process

Given the descriptions above, consider the options: (a) X-rays are emitted, (b) neutrons are emitted, (c) alpha particles are emitted, (d) gamma rays are emitted. In the context of K-electron capture, the direct result regarding predictable emissions is the emission of X-rays, due to the electron transitions filling the vacancy in the K-shell.

Key concepts

X-rays Emission

During K-electron capture, an electron from the K-shell, the innermost shell of an atom, is taken into the nucleus. This creates a vacancy in the shell that needs to be filled. Electrons from higher energy levels naturally transition down to lower levels to fill this gap.

When these electrons fall into the lower energy levels, they release energy in the form of X-rays. X-rays are a type of electromagnetic radiation that is highly energetic and capable of penetrating various materials. This emission is a hallmark of the electron transition process, specifically resulting from the gaps left by K-electron capture. These X-rays help illustrate the changes occurring within the electron shells of an atom during nuclear reactions.

X-ray emission is characteristic of certain elements since each element has specific energy levels. Thus, the energy of emitted X-rays corresponds to the specific element undergoing the transition.

Gamma Rays Emission

K-electron capture leads to an unstable nucleus, which often needs to release excess energy to reach a stable state. This energy is frequently emitted in the form of gamma rays.

Gamma rays are a form of electromagnetic radiation with a very high energy, even higher than X-rays. Unlike other emissions like alpha or beta particles, gamma rays are photons, meaning they have no mass or charge. This makes them highly penetrating.

The emission of gamma rays typically follows the initial electron capture because the capture often results in an excited nuclear state. The nucleus then sheds this energy by emitting gamma rays, allowing it to settle back into a lower energy, more stable state. This process helps stabilize the atom but is not the primary emission event in K-electron capture.

Electron Transitions

The concept of electron transitions is critical in understanding K-electron capture. When an electron is captured from the K-shell, it leaves behind a vacancy.

Electrons from higher energy levels will transition to fill this vacancy. These transitions are shifts from higher to lower energy states and involve the release of energy.

The downward transitions of electrons from higher to lower energy levels are accompanied by the emission of electromagnetic radiation. In the context of K-electron capture, this radiation is typically in the form of X-rays, as higher shell electrons fall into the empty K-shell. This emitted radiation provides a clear signature that can be used to identify and study elements.

Atomic Number Change

An essential aspect of K-electron capture is the change in atomic number. During this process, a proton in the nucleus transforms into a neutron as it captures an electron.

This transformation decreases the atomic number by one since the number of protons, which determines the element, is reduced. However, the mass number remains the same as it accounts for both protons and neutrons, which keeps the mass balance intact.

This decrease in atomic number changes the identity of the element itself, as elements are distinguished by the number of protons in the nucleus. Understanding atomic number changes is crucial when studying nuclear reactions and how they affect elemental composition.