  Analytical expressions of the one- and two-body terms in the cluster
expansion of the charge form factors and densities of the s-p and s-d shell
nuclei with N=Z are derived. They depend on the harmonic oscillator parameter b
and the parameter $\beta$ which originates from the Jastrow correlation
function. These expressions are used for the systematic study of the effect of
short range correlations on the form factors and densities and of the mass
dependence of the parameters b and $\beta$. These parameters have been
determined by fit to the experimental charge form factors. The inclusion of the
correlations reproduces the experimental charge form factors at the high
momentum transfers ($q\geq 2 1/fm$). It is found that while the parameter
$\beta$ is almost constant for the closed shell nuclei, $^4$He, $^{16}$O and
$^{40}$Ca, its values are larger (less correlated systems) for the open shell
nuclei, indicating a shell effect in the closed shell nuclei.
