What value of Z (atomic number)and A (mass number)result in the following alpha decay?
A)Z = 92;A = 238
B)Z = 91;A = 238
C)Z = 90;A = 234
D)Z = 93;A = 238
E)Z = 88;A = 236

Question

What value of Z (atomic number)and A (mass number)result in the following alpha decay? 
A)Z = 92;A = 238 
B)Z = 91;A = 238 
C)Z = 90;A = 234 
D)Z = 93;A = 238 
E)Z = 88;A = 236

Quizplus · Accepted Answer

In alpha decay, an alpha particle (which has 2 protons and 2 neutrons) is emitted. This means that the parent nucleus must have an atomic number greater than 2 and a mass number greater than 4. Looking at the given code, we see that the parent nucleus has an atomic number of 92 and a mass number of 238 (TB2295_11). Therefore, the daughter nucleus must have an atomic number of 90 (92-2) and a mass number of 234 (238-4). The correct answer is C, which matches these values.

What Value of Z (Atomic Number)and a (Mass Number)result in the Following