Question

6. Use the periodic chart to fill in all the missing items so as to make the nuclear decays complete. I.e., specify completely (i.e. including subscripts and superscripts) Z and X in each of the two separate reactions below.

92^238U + 0^1 n --> 57^140La + Z + 2 0^1n

88^226Ra --> X + 2^4 He

Answer 1

For making the nuclear decays complete, the sum total of atomic number and mass number must be the same (balanced) on both sides of the equation, given by the --> symbol.

As per the first given equation, sum total of atomic number is represented as,

92 + 0 = 57 + a_Z + (2 * 0), where a_Z = atomic number of the element Z (as atomic number is denoted by the subscripts)

Thus, a_Z = 35....(i)

Similarly, some total of mass number is represented as,

238 + 1 = 140 + m_Z + (2 * 1), where m_Z = mass number of the element Z (as mass number is denoted by the superscripts)

Thus, m_Z = 97....(ii)

Similarly, as per the second given equation, sum total of atomic number is represented as,

88 = a_X + 2, where a_X = atomic number of the element X

Thus, a_X = 86....(iii)

Likewise, some total of mass number is represented as,

226 = m_X + 4, where m_X = mass number of the element X

Thus, m_X = 222....(iv)

Thus from (i) and (ii), we have,

92^238U + 0^1 n --> 57^140La + 35^97Z + 2 0^1n

From (iii) and (iv), we have,

88^226Ra --> 86^222X + 2^4 He