The fuel used in an atomic pile is

Which one of the following statements is correct?

Consider the following nuclear reactions:
$_{92}^{238}M \to _{y}^{x}N + 2_{2}^{4}He$
$_{y}^{x}N \to _{B}^{A}L + 2\beta^{+}$
The number of neutrons in the element $L$ is:

Radioactive isotopes that have an excessive neutron/proton ratio generally exhibit

The energy required to separate a neutron and a proton from the nucleus is called:

The number of neutrons in a parent nucleus $X$,which gives a $_7N^{14}$ nucleus after two successive $\beta$ emissions,is: