1.Ā A should beĀ āāĀ²Ā³ā“Th.
Since, this is an alpha decay (āā“He decay), the daughter atom should have atomic number 92 - 2 = 90. Hence, the daughter atom is Th (Thorium). But the mass number of daughter atom reduces by 4 than parent atom. Hence mass number should be 238 - 4 = 234.
2.Ā BĀ should beĀ āāā°Ī²
Since A isĀ āāĀ²Ā³ā“Th, the produced daughter atom has atomic number as 91 which is higher than parent atom by 1 but the mass number is same as parent atom as 234. Hence, this is aĀ Ī²ā» decay. InĀ Ī²ā» decay,Ā a neutron is converted into a proton by emitting an electron. Hence, the mass number is not changed but atomic number is increased by 1 in daughter atom.
3. Ā CĀ should beĀ āāĀ²Ā³ā“U
Due to the emitted particle is an electron, this
is aĀ Ī²ā» decay.Ā In this decayĀ a neutron is
converted into a proton by emitting an electron. Since parent atom isĀ āāĀ²Ā³ā“Pa, Daughter atom should have 91 + 1 =Ā 92Ā as the atomic number. Hence, the daughter atom
should beĀ UĀ (Uranium) but mass number is same as parent
atom isĀ 234.
4. answer isĀ āāĀ²Ā³ā“U
The parent atom undergoes an alpha decay. Hence, the mass number is reduced by 4 while atomic number is reduced by 2 in the product. The product isĀ āāĀ²Ā³ā°Th, The atomic number should be 90 + 2 = 92 in Parent atom which belongs to U (Uranium). But mass number should be 230 + 4 = 234.
5. D should beĀ āāĀ²Ā²ā¶Ra.
This is an alpha decay. Hence, atomic number of daughter atom is less than atomic number of parent atom by 2 and theĀ mass number of daughter atom is less than the mass number of parent atom by 4. Since parent atom has 90 as atomic number, daughter atom should have 90 - 2 = 88 as the atomic number. Hence, the daughter atom should be Ra (Radium). But the mass number should be 230 - 4 = 226.
6.Ā EĀ isĀ āā“He.
Ā
D isĀ āāĀ²Ā²ā¶Ra. Produced daughter atom is given asĀ āāĀ²Ā²Ā²Rn. The mass number of daughter atom is reduced by 4 while
reducing the atomic number by 2 than parent atom. Hence, this is anĀ alpha
decay. Hence, the emitted particle should beĀ āā“He.
7. FĀ isĀ āā“He.
Ā
Parent atom is āāĀ²Ā²Ā²Rn. Produced daughter atom is given as āāĀ²Ā¹āøPo. The mass number of daughter atom is reduced by 4 while
reducing the atomic number by 2 than parent atom. Hence, this is anĀ alpha
decay. Hence, the emitted particle should beĀ āā“He.
8. G should beĀ āāĀ²Ā¹ā“Pb.
This is anĀ alpha decay.Ā Hence, atomic number of daughter atom is less than atomic number of parent atom by 2 andĀ theĀ mass number of daughter atom is less than the mass number of parent atom by 4.Ā Since parent atom has 84 as the atomic number, daughter atom should have 84 - 2Ā = 82Ā as the atomic number which belongs to Pb (Lead).Ā But the massĀ number should beĀ 218 - 4 = 214.
9. H isĀ āāā°Ī² (āāā°e)
Since G isĀ āāĀ²Ā¹ā“Pb, the produced daughter atom has atomic number as 82 + 1 = 83 which is higher than parent atom by 1 but the mass number is same as parent atom as 214. Hence, this is aĀ Ī²ā» decay. InĀ Ī²ā» decay,Ā a neutron is converted into a proton by emitting an electron. Hence, the mass number is not changed but atomic number is increased by 1 in daughter atom.
10. I should beĀ āāĀ²Ā¹ā“Po.
Due to the emitted particle is an electron, this is aĀ Ī²ā»Ā decay.Ā In this decayĀ a neutron is converted into a proton by emitting an electron. Since parent atom isĀ āāĀ²Ā¹ā“Bi, Daughter atom should have 83 + 1 = 84Ā as the atomic number. Hence, the daughter atom should be PoĀ (Polonium) but mass number is same as parent atom which isĀ 214.
11. J should beĀ āāĀ²Ā¹ā°Pb
Due toĀ the emitted particle isĀ āā“He, this is an alpha decay. I isĀ āāĀ²Ā¹ā“Po. After an alpha decay, the atomic numberĀ daughter atom decreases by 2 while reducing mass number by 4 than parent atom. Hence, daughter atom should have atomic number 84 - 2 = 82 which belongs to Pb (Lead). But the mass number should be 214 - 4 = 210.