  We present theoretical predictions for electron scattering on the N = 14, 20,
and 28 isotonic chains from proton-deficient to proton-rich nuclei. The
calculations are performed within the framework of the distorted-wave Born
approximation and the proton and neutron density distributions are evaluated
adopting a Relativistic Hartree-Bogoliubov (RHB) approach with a density
dependent meson-exchange interaction. We present results for the elastic and
quasi-elastic cross sections and for the parity-violating asymmetry parameter.
Owing to the correlations between the evolution of the electric charge form
factors along each chain with the underlying proton shell structure of the
isotones, elastic electron scattering experiments on isotones can provide
useful informations about the occupation and filling of the single-particle
levels of protons.
