  The chemical composition of the Sun is requested in the context of various
studies in astrophysics, among them in the calculation of the standard solar
models (SSMs), which describe the evolution of the Sun from the
pre-main-sequence to its present age. In this work, we provide a critical
re-analysis of the solar chemical abundances and corresponding SSMs. For the
photospheric values, we employ new high-quality solar observational data
collected with the IAG facility, state-of-the art non-equilibrium modelling,
new oscillator strengths, and different atmospheric models, including the MARCS
model, but also averages based on Stagger and CO5BOLD 3D
radiation-hydrodynamics simulations of stellar convection. We perform new
calculations of oscillator strengths for transitions in O I and N I. For O I -
the critical element for the interior models - calculations are carried out
using several independent methods. We find unprecedented agreement between the
new estimates of transition probabilities, thus supporting our revised solar
oxygen abundance. We also provide new estimates of the noble gas Ne abundance.
We investigate our results in comparison with the previous estimates. We
discuss the consistency of our photospheric measurements with meteoritic values
taking into account systematic and correlated errors. Finally, we provide
revised chemical abundances, leading to a new value of the solar photospheric
present-day metallicity $Z/X = 0.0225$, and employ them in the calculations of
the SSM. We find that the puzzling mismatch between the helioseismic
constraints on the solar interior structure and the model is resolved with the
new chemical composition.
