K - 39
Na-23
This the mass number of the isotope As-76.
Na-23
Unfortunately WikiAnswers doesn't accept subscript/superscript.For the isotope thorium-232: 232Th90232 is a superscript (mass number) and 90 is a subscript (atomic number).
Ar 40 is the most common isotope, accounting for 99.6% of the total (by weight).
40K
For example a thorium isotope is Th-231 or 23190 Th.
Th-234
The chemical notation is 19F.
K - 39
It is usually of the form 23Na where the 23 appears as a superscript.
It is usually of the form 23Na where the 23 appears as a superscript.
Na-23
This symbol is Tc-99m.
'Na' is the atomic notation of sodium. Hope this helps :)
Ar