What are the products of the alpha (α) and beta (β⁻) decays, respectively, in the nuclear decay chain below?

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Quizplus · Accepted Answer

11ecba2d_1249_498e_a3bf_4359b7a5a194_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 emission. During alpha (α) decay, an unstable nucleus ejects an α particle consisting of 2 protons and 2 neutrons (a helium-4 nucleus without its electrons). Accordingly, the resulting nucleus formed following an α decay will have a mass number that is 4 units less and an atomic number that is 2 units less than the nucleus that underwent the α decay. 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 is unchanged but the atomic number either increases (β⁻ decay) or decreases (β⁺ decay) by 1 unit. Consequently, the α decay of an atom of astatine-218 would form bismuth-214 by the following nuclear reaction: 11ecba2d_1249_709f_a3bf_c57c0cfa0104_MD0008_00 Subsequent β⁻ decay of the ²¹⁴Bi nucleus would eject a nuclear electron (e⁻) and yield a polonium nucleus with the same mass number: 11ecba2d_1249_70a0_a3bf_bb9b101302b1_MD0008_00 Therefore, the products of the alpha (α) and beta (β⁻) decays in the given nuclear decay chain of ²¹⁸At are ²¹⁴Bi and ²¹⁴Po, respectively. (Choices A, B, and C) In an α decay, both the mass number and the atomic number should decrease by four and two units, respectively. In a β⁻ decay, the atomic number increases by one unit. Educational objective: In α decay, the mass number of an atomic nucleus decreases by 4 units and the atomic number decreases by 2 units. 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) by 1 unit.

What Are the Products of the Alpha (α) and Beta