  Large scale calculations for the energy levels, transition rates, oscillator
strengths, hyperfine interaction constants, Land\'e g$_J$ factors and isotope
shifts have been performed for $1s^2$ and $1snl \: (n=2-8 $ and $l \leq (n-1)
)$ levels of He-like scandium, Sc XX. The GRASP2018 package based on the
multi-configurational Dirac-Fock method is used to perform these calculations.
The leading quantum electrodynamics corrections, Breit interactions and nuclear
recoil effects are also included in the succeeding relativistic configuration
interaction calculations. The relativistic isotope shift (RIS4) program is used
to determine the mass and field shifts factors. A detailed comparison of the
present results with the corresponding values from the NIST database and other
theoretical work, wherever available, has been done, and an excellent agreement
is achieved. A large section of the results is reported for the first time in
the present work.
