Question

Write down the values of M (atomic number or atomic weight) and Z (atomic number) for :

Answer 1

Answer:

(1) Z = 82, M = 208;  (2)  Z = 82, M = 208

Step-by-step explanation:

(1) Decay of Th-232

The unbalanced nuclear equation is

$_{90}^{232}\text{Th} \longrightarrow _{x}^{y}\text{Z} +6 _{2}^{4}\text{He} + 4 _{-1}^{0}\text{e}$

The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.  

Then

  90 = x + 6×2 + 4(-1), so x =   90 – 12 + 4 =   82

232 = y + 6×4 + 4×0,  so y = 232 – 24      = 208

Z = 82, M = 208

(2) Decay of U-238

The unbalanced nuclear equation is

$_{92}^{238}\text{U} \longrightarrow _{x}^{y}\text{Z} +6 _{2}^{4}\text{He} + 2 _{-1}^{0}\text{e}$

Then

  92 = x + 6×2 + 2(-1), so x =   92 – 12 + 2 =  82

238 = y + 6×4 +4×0,    so y = 238 – 24     = 214

Z = 82, M = 214