Argon (Ar) is a stable gas with a very high ionization energy. Which statement explains why? A. It has a full outer shell of electrons. B. It has 18 protons in its nucleus. C. It has 22 neutrons in its nucleus. D. It has two shells of electrons.
The answer is A. Argon is a noble gas, which means that it is group 12 of the periodic table. It is stable because it has a full outer shell of electrons.
