Negative ions, also known as anions, are atoms or molecules that have gained one or more electrons, resulting in a net negative electrical charge. This occurs because electrons carry a negative charge, and by acquiring additional electrons, the total number of negative charges (electrons) exceeds the total number of positive charges (protons in the nucleus).
Here are the key characteristics and formation of negative ions:
- Formation: Anions are formed when a neutral atom or molecule accepts one or more electrons. This process is generally energetically favorable for non-metals, which have a high electron affinity (tendency to attract electrons).
- Charge: The charge of an anion indicates how many electrons it has gained. For example, a chloride ion (Cl−) has gained one electron, while an oxide ion (O2−) has gained two electrons.
- Electron Configuration: Anions often achieve a stable electron configuration, typically resembling that of a noble gas, by gaining electrons.
- Size: Anions are generally larger than their corresponding neutral atoms because the added electrons increase electron-electron repulsion and spread the electron cloud further from the nucleus.
- Nomenclature:
- For monatomic anions (single atom), the ending of the element's name is changed to "-ide" (e.g., Chlorine becomes Chloride, Oxygen becomes Oxide).
- Polyatomic anions (ions made of multiple atoms) often have names ending in "-ate" or "-ite" (e.g., Sulfate, Sulfite, Nitrate, Nitrite), indicating the presence of oxygen, or "-ide" for some simple ones (e.g., Hydroxide).
Negative ions are crucial in countless chemical reactions, playing a vital role in forming ionic compounds, conducting electricity in solutions, and facilitating biological processes. They are attracted to positive ions, forming the basis of ionic bonding and the structure of many salts.
What specific charge of negative ions would you like a list for? For example, -1 ions, -2 ions, etc.
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