In the nuclear reaction: $X(n, \alpha) {_3Li^7}$,the term $X$ will be

Particles and their anti-particles have

Obtain approximately the ratio of the nuclear radii of the gold isotope $^{197}_{79}Au$ and the silver isotope $^{107}_{47}Ag$.

Show that the volume of a nucleus is proportional to its atomic mass number $A$.

What is the approximate percentage of the total mass of an atom that is concentrated in its nucleus (in $\%$)?

If the mass number of an atom is $A = 40$ and its electron configuration is $1s^2, 2s^2, 2p^6, 3s^2, 3p^6$,the number of neutrons and protons in its nucleus will be