Question

Identify the unknown isotope X in each of the following decays. Enter X in the form Y-A, where Y is the one or two letter chemical symbol and A is the mass number. (a) x rightarrow^224Ra + alpha (b) x rightarrow^232Th + gamma (c) x rightarrow^12C + e^- +^-v (d)^51Cr + e^- rightarrow x + v

Answer 1

1) 228Th

In this reaction X's mass number = 224 + 4 = 228

atomic number = 88 + 2

= 90

2) 232Th

In this reaction mass and atomic number does not change.

3) 12B

In this reaction X's mass number = 12

atomic number = 6 - 1

= 5

4) 51Mn

In this reaction X's mass number = 51

atomic number = 24 + 1

= 25