A uranium nucleus `U-238` of atomic number`92` emits two `alpha`- particles and two `beta`-particles and trasnforms into a thorium nucleus. What is the mass number and atomic number of the thorium nucleus so produced?

Explanation

The process is expressed as
`._(92)U^(238) rarr. _(90)Th^(230) +2(._(2) He^(4)) + 2(._(-1)beta^(0))`
The mass number of thorium nucleus is `230`and atomic number is `90`.