Fill in the blank. Oxygen ionizes to become ― 2 instead of ― 1 because O^2- is more ___________   .

Verified step by step guidance

1. Understand the context: Oxygen typically forms ions by gaining electrons to achieve a stable electronic configuration, similar to the nearest noble gas (Neon). This is due to its high electronegativity and tendency to complete its octet.
2. Recall the electronic configuration of oxygen: The neutral oxygen atom has an atomic number of 8, meaning its electronic configuration is 1s² 2s² 2p⁴. It needs 2 more electrons to fill its 2p orbital and achieve a stable octet.
3. Analyze the charge states: When oxygen gains 1 electron, it forms O⁻ (with a -1 charge). However, this state is less stable because the octet is not yet complete. When oxygen gains 2 electrons, it forms O²⁻ (with a -2 charge), achieving a full octet and a more stable configuration.
4. Consider the concept of stability: The O²⁻ ion is more stable than O⁻ because it has a complete octet, which minimizes the energy of the system. Atoms and ions tend to adopt configurations that lower their energy and increase stability.
5. Fill in the blank: The blank should be filled with the word 'stable,' as O²⁻ is more stable than O⁻ due to its complete octet and lower energy state.

Key Concepts

Ionization Energy

Ionization energy is the energy required to remove an electron from an atom or ion. For oxygen, the first ionization energy is relatively high due to its electronegativity and the stability of its electron configuration. However, the second ionization energy is even higher, which explains why oxygen typically forms a -2 charge (O²⁻) rather than a -1 charge (O⁻).

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons. Oxygen is highly electronegative, which means it has a strong tendency to gain electrons to achieve a stable octet configuration. This property contributes to its preference for forming a -2 charge, as it can effectively stabilize the additional electrons.

Stability of Electron Configuration

The stability of an electron configuration refers to how energetically favorable a particular arrangement of electrons is. For oxygen, achieving a full outer shell with eight electrons (octet) by gaining two electrons leads to the formation of the O²⁻ ion, which is more stable than having only one additional electron. This stability drives the ionization process and the resulting charge.