91影视

Consider the given chemical equation as:

${}^{235}U+n鈫�X+Y+bn$.

From the atomic and mass numbers given, determine the unknown isotope as well as the value of b.

Note that the sum of superscripts (mass numbers A) must balance, as well as the sum of Z values (where reference to Appendix F or G is helpful). A neutron has Z=0 and A=1. Uranium has Z=92.

Since xenon has Z=54, then 鈥淵鈥� must have Z=92-54=38, which indicates the element strontium. The mass number of 鈥淵鈥� is

235+1-140-1=95

So 鈥淵鈥� is ${}^{95}Sr$.

Iodine has Z=53, so 鈥淵鈥� has Z=92-53=39, corresponding to the element yttrium (the symbol for which, coincidentally, is Y).

Since 235+1-139-2=95, then the unknown isotope is ${}^{95}Y$.

The atomic number of zirconium is Z=40. Thus,92-40-2 , which means that 鈥淴鈥� has Z=52 (tellurium). The mass number of 鈥淴鈥� is 235+1-100-2=134, so we obtain ${}^{134}Te$.

Examining the mass numbers solve as:

$$\begin{gathered} b=235+1-141-92 \\ =3 \end{gathered}$$

The completed table is shown below: