Answer:
The nuclear fuel used in a nuclear reactor needs to have a higher concentration of the U 235 isotope than that which exists in natural uranium ore. U235 when concentrated (or "enriched") is fissionable in light-water reactors (the most common reactor design in the USA).
Explanation:
The eletron pairs repel each other in a tetrahedral shape.
The answer is Liquid iron.
(1) a beta particle is your answer. Na-24 decays through beta decay, turning a neutron into a proton, electron (beta particle), and an neutrino.
hydrogen and helium and the most abundant elements in a nebula.