  Element abundance ratios of magnesium to neon (Mg/Ne) and neon to oxygen
(Ne/O) in the transition region of the quiet Sun have been derived by
re-assessing previously published data from the Coronal Diagnostic Spectrometer
on board the Solar and Heliospheric Observatory in the light of new atomic
data. The quiet Sun Mg/Ne ratio is important for assessing the effect of
magnetic activity on the mechanism of the first ionization potential (FIP)
effect, while the Ne/O ratio can be used to infer the solar photospheric
abundance of neon, which can not be measured directly. The average Mg/Ne ratio
is found to be $0.52\pm 0.11$, which applies over the temperature region
0.2--0.7~MK, and is consistent with the earlier study. The Ne/O ratio is,
however, about 40\%\ larger, taking the value $0.24\pm 0.05$ that applies to
the temperature range 0.08--0.40~MK. The increase is mostly due to changes in
ionization and recombination rates that affect the equilibrium ionization
balance. If the Ne/O ratio is interpreted as reflecting the photospheric ratio,
then the photospheric neon abundance is $8.08\pm 0.09$ or $8.15\pm 0.10$ (on a
logarithmic scale for which hydrogen is 12), according to whether the oxygen
abundances of M.~Asplund et al.\ or E.~Caffau et al.\ are used. The updated
photospheric neon abundance implies a Mg/Ne FIP bias for the quiet Sun of
$1.6\pm 0.6$.
