Question

Which of the following isotopes would you expect to be stable?  

Answer 1

correct answer is option-1 option 2, option 4 is correct

Nuclei with even numbers of protons and neutrons are generally more stable than nuclei with odd numbers of protons and neutrons

nuclei with "magic numbers" of protons (2, 8, 20, 28, 50, 82) or neutrons (2, 8, 20, 28, 50, 82) are generally more stable than nuclei without magic numbers of protons or neutrons

lets see one by one

Carbon - 12

no o fproton = 6 no of nuetron = 6

both are even number and both are majic number so this is stable

⁴He

protons = 2 and nuetrons = 2

so this is also stable

U-238

no of protons = 92

nuetrons = 146 no magic numbers

All nuclei with an atomic number greater than 83 are radioactive so less stable

so less stable

58Ni is stable and

208Po is not stable