How Many Electrons Does O2- Have?
Understanding the electron configuration of ions is fundamental in chemistry. Let's delve into the specifics of the oxide ion, O2-.
Oxygen's Neutral State
A neutral oxygen atom (O) has 8 electrons. This is determined by its atomic number, which is also 8. This means it has 8 protons in its nucleus, balanced by 8 electrons orbiting the nucleus.
Forming the Oxide Ion (O2-)
The oxygen atom achieves a more stable electron configuration by gaining two electrons. This process creates the oxide ion, denoted as O2-.
Electron Count in O2-
By gaining two electrons, the oxide ion (O2-) now possesses a total of 10 electrons. These 10 electrons fill its energy levels, making it isoelectronic with Neon (Ne), a noble gas with a stable octet.
Why Two Electrons?
Oxygen, like other elements in Group 16 (chalcogens), is highly reactive because it is two electrons short of a full outer electron shell (the octet rule). Gaining these two electrons is energetically favorable, leading to the formation of the stable O2- ion.
In Summary
To reiterate, the oxide ion (O2-) has 10 electrons. This is a crucial concept in understanding ionic bonding and the behavior of oxygen in chemical compounds.
