Select the correct answer.
Polonium-210 decays once before it becomes a stable atom. What is that stable atom?
[tex] {}_{84}^{210} Po \rightarrow \ldots+{ }_2^4 He [/tex]
A. [tex] {}_{82}^{206} Pb [/tex]
B. [tex] {}_{84}^{210} Po ^{-} [/tex]
C. [tex] {}_{86}^{214} Rn [/tex]
D. [tex] {}_{86}^{222} Rn [/tex]
E. [tex] {}_{82}^{214} Pb [/tex]
Answer (2)
Polonium-210 decays by emitting an alpha particle.
The mass number of the resulting atom is calculated by subtracting 4 from the mass number of Polonium-210: 210 − 4 = 206 .
The atomic number of the resulting atom is calculated by subtracting 2 from the atomic number of Polonium-210: 84 − 2 = 82 .
The stable atom with atomic number 82 and mass number 206 is 82 206 P b .
Explanation
Understanding the Problem We are given the nuclear decay of Polonium-210 and asked to identify the stable atom produced after the decay. Polonium-210 ( 84 210 P o ) decays by emitting an alpha particle ( 2 4 He ). An alpha particle consists of 2 protons and 2 neutrons.
Setting up the Equation The nuclear decay equation can be written as: 84 210 P o → Z A X + 2 4 He where Z A X represents the unknown stable atom.
Calculating the Mass Number To find the mass number (A) of the stable atom, we subtract the mass number of the alpha particle from the mass number of Polonium-210: A = 210 − 4 = 206
Calculating the Atomic Number To find the atomic number (Z) of the stable atom, we subtract the atomic number of the alpha particle from the atomic number of Polonium-210: Z = 84 − 2 = 82
Identifying the Element The element with atomic number 82 is Lead (Pb). Therefore, the stable atom produced is Lead-206, which is represented as 82 206 P b .
Final Answer The stable atom is 82 206 P b .
Examples
Nuclear decay is used in various applications, such as radioactive dating to determine the age of ancient artifacts and geological formations. For example, the decay of carbon-14 is used to date organic materials, while the decay of uranium-238 is used to date rocks. Understanding nuclear decay helps us learn about the history of the Earth and the universe.
The stable atom produced from the decay of Polonium-210 is Lead-206, denoted as 82 206 Pb . Therefore, the correct answer is option A: 82 206 Pb .
;
