Explain how covalent bonds hold you Molcules together

How are isotopes of the same chemical element alike? how are they different?

Ill give brainiestif one neutron initiates a fission event that produces two neutrons in the products, how many new reactions can now be initiated? if each of the neutrons produced in the first fission event then initiates a fission event that produces one neutron in the products, how many new reactions can now be initiated by each neutron? how many neutrons in total were produced by the two fission events described?

Ab c or d ? i’m not sure what the answer is