Regarding chemical elements such as argon that are inert, which of the following statements is true?
A. They regularly lose several of their outer electrons when reacting.
B. They have twice as many protons as electrons.
C. They don't react with other elements to form compounds.
They easily react with other elements In form chemical bonds

C. They don't react with other elements to form compounds

Explanation:

The elements in Group 18 of the periodic table are called "inert", or noble gases.

These elements have their valence shell (the outermost shell of the atom) full of electrons, so they do not gain/give off electrons, and therefore, they do not react with other elements, so they do not form compounds.

In fact, normally the elements try to gain/give off electrons in order to fullfill their outermost shell (the valence shell). For instance, an atom that has 1 electron only in its valence shell, try to "give away" this electron in order to have its outermost shell completed. On the other hand, an atom which has 7 electrons in its valence shell tries to "gain" one electron in order to fullfill the valence shell.

Noble gases, instead, have already 8 electrons in their valence shell, so their valence shell is already completed, therefore they do not react with other elements, and therefore they are called "inert".