Manganese-54 can undergo a β⁻ decay that is followed by two positron emissions (β⁺ decays), or it can undergo a gamma decay (γ) that is followed by electron capture ε (a form of β⁺ decay). Which of the following diagrams correctly describes the nuclear decay chain of ⁵⁴Mn?

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Quizplus · Accepted Answer

11ecba2d_1248_8635_a3bf_57d73f75ae23_MD0008_00 Radioactivity is the spontaneous emission of radiation (photons or particles) from an unstable atomic nucleus. Although several types of nuclear radiation exist, the three most common types are alpha decay, beta decay, and gamma decay. During gamma decay, an unstable nucleus in an excited state releases excess energy by emitting a gamma ray (γ), which is a high-energy photon (an electromagnetic wave packet). One characteristic of gamma emission is that the number of protons and neutrons in the nucleus remains the same. As a result, the elemental identity of a nucleus is unchanged by gamma emission. For example, the gamma decay of ⁵⁴Mn yields: 11ecba2d_1248_8636_a3bf_993a7ffc59b6_MD0008_00 Beta decay can occur in three forms: β⁻ decay (electron emission), β⁺ decay (positron emission), and electron capture. In all three forms of beta decay, the mass number remains unchanged but the atomic number either increases (β⁻ decay) or decreases (β⁺ decay, electron capture) by 1 unit. In β⁻ decay, a neutron converts to a nuclear proton and emits an electron (e⁻) and an antineutrino ( 11ecba2d_1248_8637_a3bf_ffc9cf5965ea_MD0008_00 For example, the β⁻ decay of ⁵⁴Mn yields: 11ecba2d_1248_8638_a3bf_ef0f01cb19d8_MD0008_00 In β⁺ decay, a nuclear proton converts to a neutron (the opposite of β⁻ decay) and ejects a positron (e⁺) and a neutrino ( 11ecba2d_1248_ad49_a3bf_83f6ed78837b_MD0008_00 . For example, the β⁺ decay of ⁵⁴Fe yields: 11ecba2d_1248_ad4a_a3bf_7fb768920d08_MD0008_00 And a subsequent β⁺ decay of ⁵⁴Mn yields: 11ecba2d_1248_ad4b_a3bf_7741bf44a12d_MD0008_00 In electron capture, a proton captures an electron near the nucleus and converts to a neutron without a positron or electron emission. For example, nuclear decay of ⁵⁴Mn by electron capture yields: 11ecba2d_1248_ad4c_a3bf_5bbc28fbf505_MD0008_00 Based on these principles and the examples given above, only the diagram with ⁵⁴Fe as the product of β⁻ decay and ⁵⁴Cr as the electron-capture product (Choice C) correctly describes the full decay chain of ⁵⁴Mn. Educational objective: In gamma decay, a high-energy photon is released from a nucleus and the mass number, atomic number, and elemental identity remain unchanged. In all forms of beta decay, the mass number of an atomic nucleus remains unchanged but the atomic number increases (β⁻ decay) or decreases (β⁺ decay, electron capture) by 1 unit.

Manganese-54 Can Undergo a β− Decay That Is Followed by Two

Manganese-54 Can Undergo a β⁻ Decay That Is Followed by Two