Answer is: zirconium-98. Nuclear reaction: ²³⁵U + n°→ ¹³⁵Te + ⁹⁸Zr + 3n°. Atomic number of uranium is 92, atomic number of zirconium (Zr) is 40 and atomic number of tellurium (Te) is 52, 92 = 40 + 52. Uranium has atomic mass 235, zirconium has 98 and tellurium has 135: 235 + 1 = 135 + 98 +3, 236 = 236. n° is neutron. Symbol for atomic number is Z and for atomic mass is A.
