What is the name of the isotope produced when californium-251 emits an alpha particle?

                 Curium-247 i.e. ²⁴⁷₉₆Cm

Alpha decay is given by following general equation,

                              ᵃₓA    →    ⁴₂He  +  ᵃ⁻⁴ₓ₋₂B

Where;

           A  =  Parent Isotope

           B  =  Daughter Isotope

           ᵃ  =  Mass Number

           ₓ  =  Atomic Number

Californium-251 is the parent isotope in our case and it has 98 protons (atomic number) and is given as,

                                                 ²⁵¹₉₈Cf

The alpha decay reaction of Californium-251 will be as,

                               ²⁵¹₉₈Cf     →     ⁴₂He  +  ²⁴⁷₉₆B

The symbol for B with atomic number 96 was found to be the atom of Curium (Cm) by inspecting periodic table. Hence, the final equation is as follow,

                               ²⁵¹₉₈Cf     →     ⁴₂He  +  ²⁴⁷₉₆Cm

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