Yaarel
🇮🇱 🇺🇦 He-Mage
In my games, "Radiant" is literal light, electromagnetic radiation involving photons.if you wish to move a radiation as we know it away from radiation of holy light as the game defines it, might I suggest the first be called atomic damage makes it clear of what it is.
Also, Radiant represents "plasma", the gas-like electrical state of matter, found in the sun, stars, lightning, and cold plasma, including the "dark fire" of the plasmosphere around Earth and the light tubes in the ceilings of kitchens and offices.
Water (H20) is neither "acidic" nor "base/alkaline".water is acid
Acid is more like "salts", specifically it is a chemical reaction of a molecule or ion, whence an aspect of Earth.
I give Lightning-Thunder to Air for thematic reasons, including sky beings in mythology.earth has either thunder(earthquakes) or weapon.
I view Cold as the "icy" aspect of Water.cold is not water, cold is not.
Thematically hot Fire and Cold water are opposites.
Vacuum is part of Void.elemental absence a vacuum of energy
Magical "cold" is anti-fire.hence why Ice breath attacks are the least realistic of all damage types even more so that Godzilla's radioactive particle beam.
Linking Water with ice, snow, icestorms, winter, and "coldness" generally is thematically useful.
Water can inflict Weapon damage (but I tend to allocate this to Earth themes).