- #1
andyrk
- 658
- 5
Why does the hydroxide ion have a negative charge? , i.e OH-?
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Discussion Overview
The discussion centers around the negative charge of the hydroxide ion (OH-), exploring the reasons behind its charge from various chemical perspectives. Participants reference concepts such as the octet rule, Lewis dot structures, and the distinction between ions and radicals.
Discussion Character
- Exploratory
- Technical explanation
- Conceptual clarification
- Debate/contested
Main Points Raised
- Some participants suggest that the negative charge of the hydroxide ion is due to the need for oxygen to achieve stability by gaining an additional electron, as indicated by the octet rule.
- Others propose that if the hydroxide ion were not negatively charged, it would be classified as a hydroxide radical rather than an ion.
- A participant presents a reaction involving O2- and H+, arguing that the interaction results in a remaining electron that contributes to the negative charge of the hydroxide ion.
- Some participants emphasize the importance of counting protons and electrons to understand the charge of the ion, noting that ions are charged while radicals can be neutral.
- There is a discussion about the nature of radicals, with one participant pointing out that radicals do not always have to be neutral, citing examples such as the superoxide anion.
- A clarification is made regarding the definition of radicals, indicating that they can be atoms, ions, or molecules with unpaired electrons.
Areas of Agreement / Disagreement
Participants express differing views on the relationship between hydroxide ions and radicals, with some asserting that radicals are typically neutral while others provide counterexamples. The discussion remains unresolved regarding the broader implications of these definitions and classifications.
Contextual Notes
Participants reference specific chemical concepts and examples, but there are unresolved assumptions regarding the definitions of ions and radicals, as well as the stability of various species mentioned.
- #2
DrDu
Science Advisor
- 6,423
- 1,004
Because if not, it would be a hydroxide radical and not an ion?
- #3
ArielRodriguez
- 6
- 0
Think octet rule and lewis dot structures... you need one more electron to make the oxygen stable, so it has a 1- charge.
- #4
adjacent
Gold Member
- 1,552
- 62
The simplest way for explaining this is this:andyrk said:
O2-+H+=(OH)- (It's actually (OH)-)
This is not stable(Stable form is H2O)
Here H+ Cancels out one electron of O2-
So one electron is left.Therefore it is left with a negative charge
-2+1=-1
- #5
Enigman
- 647
- 311
andyrk said:
Count the number of protons and number of electron in the ion.
With reference to what Drdu said: ions are charged, radicals are neutral.
chemistry sometimes overcomplicates things to simplify them...- #6
Yanick
- 402
- 22
Enigman said:Count the number of protons and number of electron in the ion.
With reference to what Drdu said: ions are charged, radicals are neutral.
Radicals need not always be neutral.
See: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2644638/
Also you can have stuff like the superoxide anion which is a anion radical. See: http://en.wikipedia.org/wiki/Superoxide
Plenty of examples around, these are just off the top of my head.
- #7
Enigman
- 647
- 311
Yanick said:
Sorry for not being clearer, I was talking about hydroxyl radicals which DrDu mentioned rather than radicals in general.
As for the definition of radical I believe the only prerequisite is having an unpaired electron/ incompletely filled valence shell and the species in question may be an atom, ion or a molecule.
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