explain why oxygen "likes" to form an O^2- ion.
O2 is a molecule, not an ion. O2 is stable in the outer electron configuration.
Oxygen has 8 electrons in its outermost energy level, also known as the valence shell. This outermost shell can hold a maximum of 8 electrons. However, oxygen only has 6 valence electrons. To achieve a more stable and full valence shell, oxygen "likes" to gain 2 additional electrons, which results in a negative charge of -2. This process forms the O^2- ion, also known as the oxide ion.
To understand why oxygen prefers to gain 2 electrons instead of losing 6 electrons, let's consider the concept of ionization energy and electron affinity. Ionization energy refers to the energy required to remove an electron from an atom or ion, while electron affinity refers to the energy released or absorbed when an atom gains an electron.
In the case of oxygen, it has a relatively high ionization energy, which means that removing one or more electrons from oxygen requires a significant amount of energy. On the other hand, oxygen has a high electron affinity, meaning that it readily accepts electrons. Thus, it is more energetically favorable for oxygen to gain 2 electrons to achieve a stable electron configuration, rather than losing 6 electrons to achieve a full valence shell.
Therefore, oxygen "likes" to form an O^2- ion by gaining 2 electrons, which allows it to attain a stable electron configuration and a full valence shell.