The elements you're asking about appear to refer to their atomic numbers. In that context:
- 3A – This likely refers to Lithium (Li), which has an atomic number of 3.
- 8B – This corresponds to Oxygen (O), which has an atomic number of 8.
- 12C – This indicates Magnesium (Mg), which has an atomic number of 12.
- 19E – This corresponds to Potassium (K), which has an atomic number of 19.
None of these elements are noble gases. The noble gases in the periodic table are Helium (He, atomic number 2), Neon (Ne, atomic number 10), Argon (Ar, atomic number 18), Krypton (Kr, atomic number 36), Xenon (Xe, atomic number 54), and Radon (Rn, atomic number 86).
If you have specific symbols or further clarification about the convention you're using for naming these elements, please let me know!
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