In the given radioactive decay if the mass number and atomic number of D2 are 176 and 71 respectively.What is the mass number and atomic number of D? D----->D1------->D2 Bita alpha particle

1 Answer
Mar 1, 2018

Well,though not clearly mentioned,considering,the reaction to be,

D ------> D_1 + beta ------> D_2+alphaDD1+βD2+α

Given, mass number of D_2D2 is 176176, now as D_2D2 has been formed from D_1D1 due to alphaα emission,mass number of D_1D1 must be (176+4)-180(176+4)180 and similarly atomic number should be 71+2=7371+2=73 (as, alpha particle has mass number 44 and atomic number 22)

So, we can complete the 2nd2nd half of the reaction,

""_73^180 D_2 -------> ""_71^176 D_3 + ""_2^4 He18073D217671D3+42He

Similarly, we can say, there will be no change in mass number of DD as,beta particle has mass number of 00 as beta emission is expressed as, ""_(-1)^ 0 beta01β,So its atomic number must decrease by 11 i.e 7272

So,the whole reaction becomes,

""_72^180 D ---->""_73^180 D_2 + ""_-1^0 beta -------> ""_71^176 D_3 + ""_2^4 He18072D18073D2+01β17671D3+42He