1. A should be ₉₀²³⁴Th.
Since, this is an alpha decay (₂⁴He 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. B should be ₋₁⁰β
Since A is ₉₀²³⁴Th, 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 a β⁻ decay. In β⁻ decay, 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. C should be ₉₂²³⁴U
Due to the emitted particle is an electron, this
is a β⁻ decay. In this decay a neutron is
converted into a proton by emitting an electron. Since parent atom is ₉₁²³⁴Pa, Daughter atom should have 91 + 1 = 92 as the atomic number. Hence, the daughter atom
should be U (Uranium) but mass number is same as parent
atom is 234.
4. answer is ₉₂²³⁴U
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 is ₉₀²³⁰Th, 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 be ₈₈²²⁶Ra.
This is an alpha decay. Hence, atomic number of daughter atom is less than atomic number of parent atom by 2 and the 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. E is ₂⁴He.
D is ₈₈²²⁶Ra. Produced daughter atom is given as ₈₆²²²Rn. The mass number of daughter atom is reduced by 4 while
reducing the atomic number by 2 than parent atom. Hence, this is an alpha
decay. Hence, the emitted particle should be ₂⁴He.
7. F is ₂⁴He.
Parent atom is ₈₆²²²Rn. Produced daughter atom is given as ₈₄²¹⁸Po. The mass number of daughter atom is reduced by 4 while
reducing the atomic number by 2 than parent atom. Hence, this is an alpha
decay. Hence, the emitted particle should be ₂⁴He.
8. G should be ₈₂²¹⁴Pb.
This is an alpha decay. Hence, atomic number of daughter atom is less than atomic number of parent atom by 2 and the mass number of daughter atom is less than the mass number of parent atom by 4. Since parent atom has 84 as the atomic number, daughter atom should have 84 - 2 = 82 as the atomic number which belongs to Pb (Lead). But the mass number should be 218 - 4 = 214.
9. H is ₋₁⁰β (₋₁⁰e)
Since G is ₈₂²¹⁴Pb, 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 a β⁻ decay. In β⁻ decay, 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 be ₈₄²¹⁴Po.
Due to the emitted particle is an electron, this is a β⁻ decay. In this decay a neutron is converted into a proton by emitting an electron. Since parent atom is ₈₃²¹⁴Bi, Daughter atom should have 83 + 1 = 84 as the atomic number. Hence, the daughter atom should be Po (Polonium) but mass number is same as parent atom which is 214.
11. J should be ₈₂²¹⁰Pb
Due to the emitted particle is ₂⁴He, this is an alpha decay. I is ₈₄²¹⁴Po. After an alpha decay, the atomic number 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.
