Question

A thorium isotope ( mass number – 223 and atomic number – 90) undergoes an α decay and changes into radium. What is the atomic number and mass number of the radium produced?

Answer 1

Answer:

given =  thorium isotopes mass number = 223 and atomic number  226

to find = atomic number and mass number of radium

solution :-

₉₀Th²³⁰  -------->₂ He⁴ + ₈₈Ra²¹⁹  

hence atomic number of radium is 88

atomic mass number of radium is 219

alternative metho of finding atomic and mass number

atomic number is = 90-2 = 88

mass number = 223 -4 = 219