Final answer:
True, the most stable charge state for an isolated oxygen atom is -2 because by gaining two electrons, oxygen achieves a full valence shell similar to noble gases, which is highly stable.
Step-by-step explanation:
The statement "The most stable charge state for an isolated oxygen atom is -2" is true. An oxygen atom has six electrons in its valence shell, and it requires two additional electrons to achieve a full outer shell, which corresponds to a stable noble gas electron configuration. By gaining two electrons, oxygen achieves a -2 charge, which is its most common and stable oxidation state, especially when forming compounds. For instance, in water (H2O), oxygen has a -2 charge.
Oxygen can form different oxidation states under certain conditions, like +2 in OF2 due to fluorine's higher electronegativity, or -1/2 in superoxides like KO2. However, these are less common and typically occur due to unique bonding circumstances. In covalent bonding scenarios, such as in oxygen gas (O=O), oxygen atoms share two pairs of electrons in a double covalent bond to fill their valence shells without formally achieving a -2 charge state.