In nuclear physics, beta (β) decay of a typical radioactive nucleus results in the emission of which type of particle?

Introduction / Context:
Radioactive decay is a process in which unstable atomic nuclei transform into more stable configurations by emitting particles or electromagnetic radiation. The main types of decay are alpha, beta, and gamma. Beta decay is especially important in nuclear physics and particle physics because it involves changes in the atomic number without major changes in mass number. This question asks you to identify which particle is emitted in a typical beta decay process as taught at school level.

Given Data / Assumptions:

• The focus is on standard beta minus (β minus) decay commonly discussed in basic nuclear physics.
• We are not considering advanced cases such as beta plus decay unless explicitly stated.
• Options list electron, proton, neutron, and all of the above.
• We assume a typical neutron rich nucleus undergoing beta decay.

Concept / Approach:
In beta minus decay, a neutron in the nucleus transforms into a proton, an electron, and an antineutrino. The proton remains in the nucleus, increasing the atomic number by one, while the electron and antineutrino are emitted. The emitted electron is called a beta minus particle or simply beta particle. Thus, from the point of view of what leaves the nucleus as observable charged radiation, beta decay is characterised by the emission of high energy electrons. Protons and neutrons are involved in internal transformations but are not emitted in typical beta minus decay at this level of discussion.

Step-by-Step Solution:
Step 1: Recall the basic reaction for beta minus decay: neutron transforms into proton plus electron plus antineutrino. Step 2: Recognise that the proton produced stays inside the nucleus, so the element changes to the next higher atomic number. Step 3: Understand that the electron produced is ejected from the nucleus at high speed and is detected as beta radiation. Step 4: Note that no free neutron is emitted in typical beta minus decay; the neutron is the particle that changes internally. Step 5: Conclude that the characteristic emitted particle in beta decay is an electron, known as a beta minus particle.

Verification / Alternative check:
Historical experiments on beta radiation showed that beta rays are deflected by electric and magnetic fields in the same way as high speed electrons, confirming that they consist of electrons. Alpha radiation was found to be helium nuclei, while gamma radiation is electromagnetic. Nuclear notation for beta decay also uses the symbol 0 -1 e to represent the emitted electron. In more advanced treatments, beta plus decay involves emission of a positron, but at basic level, when the term beta decay is used without qualification, it usually refers to beta minus decay with electron emission.

Why Other Options Are Wrong:
A proton: In beta minus decay, a proton is formed inside the nucleus but is not emitted; the nucleus retains it, leading to a new element with higher atomic number. A neutron: Beta decay starts from a neutron rich nucleus; free neutrons are not typically emitted in this process in basic examples. All of the above simultaneously: The nucleus does not emit all these particles at once in standard beta minus decay, so this option is incorrect.

Common Pitfalls:
Students sometimes mix up what happens inside the nucleus with what comes out, leading to confusion between internal transformations and emitted radiation. It is helpful to think of the neutron changing identity inside the nucleus and ejecting only the electron and neutrino. Another confusion arises between alpha and beta decay; alpha decay emits heavy helium nuclei, whereas beta decay emits light electrons or positrons. Keeping these differences clear helps in answering nuclear physics questions correctly.

Final Answer:
In typical beta (β minus) decay, the nucleus emits an electron, known as a beta minus particle.