Can someone help me with science

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?

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

Convert the temperature of dry ice, –77 ∞c, into degrees fahrenheit and kelvin.