  Theoretical physical-chemical models for the formation of planetary systems
depend on data quality for the Sun's composition, that of stars in the solar
neighbourhood, and of the estimated "pristine" compositions for stellar
systems. The effective scatter and the observational uncertainties of elements
within a few hundred parsecs from the Sun, even for the most abundant metals
like carbon, oxygen and silicon, are still controversial. Here we analyse the
stellar production and the chemical evolution of key elements that underpin the
formation of rocky (C, O, Mg, Si) and gas/ice giant planets (C, N, O, S). We
calculate 198 galactic chemical evolution (GCE) models of the solar
neighbourhood to analyse the impact of different sets of stellar yields, of the
upper mass limit for massive stars contributing to GCE ($M_{\rm up}$) and of
supernovae from massive-star progenitors which do not eject the bulk of the
iron-peak elements (faint supernovae). Even considering the GCE variation
produced via different sets of stellar yields, the observed dispersion of
elements reported for stars in the Milky Way disk is not reproduced. Among
others, the observed range of super-solar [Mg/Si] ratios, sub-solar [S/N], and
the dispersion of up to 0.5 dex for [S/Si] challenge our models. The impact of
varying $M_{\rm up}$ depends on the adopted supernova yields. Thus,
observations do not provide a constraint on the M$_{\rm up}$ parametrization.
When including the impact of faint supernova models in GCE calculations,
elemental ratios vary by up to 0.1-0.2 dex in the Milky Way disk; this
modification better reproduces observations.
