Keep getting this wrong please help

Which step in naming unsaturated hydrocarbons is used for alkenes but not alkynes

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?