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Why do only heavy radioactive elements perform fission?
Why do only heavy radioactive elements perform fission? I mean what's so special about heavy elements which makes them ideal for nuclear fission?
Also why do only neutrons show fission/fusion and why can't electrons preform fission/fusion?

Is electric potential energy responsible for energy release in nuclear fission and nuclear potential energy in fusion? What if elec. force not exist?
It was my doubt and I thought it may be electric potential energy which is responsible for energy release in nuclear fission and by bombarding neutron we only provide energy to nucleons to cross equilibrium point (Felectric = Fnuclear) then it is spontaneous separated because of excess electric force, energy stored in electric field is released when it separates. Is it true? If yes then with this approach please explain why in lighter elements energy supplied is more than energy released in case of fission?

Radioactivity and nuclear fission
Can an unstable atom undergo both nuclear fission and radioactive decay?
Other than the fact that that fission has to be initiated is there a difference between the final stability of the atoms?

Why is the alpha, beta or gamma decay of an unstable nucleus unaffected by the chemical situation of an atom, such as the nature of the molecule or solid in which it is bound? The chemical situation of the atom can, however, have an effect on the half life in electron capture. Why is this so?

Electric potential energy after nuclear fission
We have a uranium-236 nucleus that fissions into two equal fragments, and I'm supposed to find the electrical potential energy just as the two fragments split apart. No other information is provided.
I am very confused about this problem for two reasons. First, U-236 is electrically neutral, with exactly 92 protons and 92 electrons. After it splits into two equal fragments, why would there be a charge on the resulting pieces? Secondly, electric potential energy of two point charges is inversely proportional to the distance r between the particles. But since the question asks for the potential energy immediately after fission, r=0 and potential energy goes to infinity.
I'm appreciate any guidance!

Binding Energy and Stability in Nuclear fission
I've read that particles in nuclear fission disintegrates into two particles with higher binding energy, and in this process energy is released. Now I am just trying to understand this by common sense, but I am not able to. Because the particle with lower binding energy makes particles of total net higher binding energy, meaning that it takes more energy for the particles with higher binding energy to be formed from the particle with lower binding energy. Hence, shouldn't energy actually be absorbed in this process? Could someone explain where is my reasoning wrong?

Why is a nuclear fusion reactor not currently possible?
Nuclear fission reactors are fairly common, but what technological/physical limitations are currently impeding developing the nuclear fusion reactor? The H-bomb is capable of creating nuclear fusion on earth, so the process of creating nuclear fusion is already understood to some extent, although you are detonating a fission bomb to start the fusion process.
Having a cycle between a fusion and a fission reactor would solve some serious energy problems.

I have studied about nuclear reactors and also know their functionality.But some how i couldn't get answers for some my questions.
1) During fission reaction enormous amount of heat is produced and this heat is in the form of flames?
2)If so does the whole reactor core is burnt?and how come water can be in contact with the burning core?
3)Once a fission process is finished will reactor be ready for next usage or it will left for years for less radioactive?
4) Whether the chain reaction is started by introducing neutrons or done automatically by spontaneous emission of fuel rods?
5)If it is due to neutron introduction then how these neutrons attack the pellets containing uranium correctly and how many tries are required?
I have searched for many sources online but couldn't get a clear image.Hope get now.

How does the reversibility of physics interact with nuclear fission
The laws of physics are reversible and quantum information is never destroyed.
Given this, how do I time reverse the $U_{235}$ fission reaction, n which
${}_0^{1}n+{}_{92}^{235}U\to <!--\; \to \; -->{}_{56}^{141}Ba+{}_{36}^{92}Kr+3{}_0^{1}n+\mathrm{\gamma <!--\; \gamma \; -->}+$ 202.5 MeV (in kinetic energy plus gamma ray energy).
That is, would reversibility require that if we bring together the $Ba$, $Kr$, $3ns$, and the $\mathrm{\gamma <!--\; \gamma \; -->}$ all at the same instant, a $U$-$235$ and a neutron might just pop out with a certain probability?

Which is more: Energy released by nuclear fission or fusion?
The energy released by one fission reaction is 190MeV and the energy released by one fusion reaction is 24.7MeV. Then by my common sense 190>24.7 so energy released by fission>fusion but the energy released by fusion reaction is 3 to 4 times greater than fission. Please explain me how. I hope 190>24.7

Nuclear fission or fusion occurring at or near the speed of light
Suppose a device or object were traveling at or near the speed of light, and fission or fusion occurred while in this state of motion, creating an enormous blast, what would occur? Would this cause an acceleration of the objects or particles immediately in front of this blast? Or would some other event occur that I am unfortunately unaware of?