How should particle radius change upon reduction of the particle?
The size of an atom OR an anion OR a cation is determined by the radius of its valence electrons......
But when we reduce an atom, we add an electron to the valence shell. Electron-electron repulsion is not compensated for by nuclear charge (which remains constant), and thus the anionic radius should be intrinsically greater than atomic radius.
As chemists, as physical scientists, however, we should interrogate the data.......
Dimensions are in
In the process of formation of an anion we add an electron to the atom .
As a result the total no. of electrons exceeds the total no. of protons , therefore the repulsion between the electrons and protons increases and the atom expands in size.