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Topic: Phosphate has -3 charge. Why and how?  (Read 9624 times)

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Offline yodalr

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Phosphate has -3 charge. Why and how?
« on: October 06, 2018, 08:19:54 AM »
Why is it exactly -3? Can it be more or less. What caused it to have -3 charge. The book only tells me that it has -3, but I can't find explanation anywhere.

Offline chenbeier

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Re: Phosphate has -3 charge. Why and how?
« Reply #1 on: October 06, 2018, 08:26:02 AM »
Phosphate is PO43-.

You can calculate: Phosphorus has 5 Electrons to spend and you have 4 Oxygen which can accept 2 electrons each, what means 8 Electrons. You have -8 +5 = -3

Offline yodalr

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Re: Phosphate has -3 charge. Why and how?
« Reply #2 on: October 07, 2018, 09:54:02 AM »
Phosphate is PO43-.

You can calculate: Phosphorus has 5 Electrons to spend and you have 4 Oxygen which can accept 2 electrons each, what means 8 Electrons. You have -8 +5 = -3

I see, thanks.

So the overall charge is still 0 yes? Only oxygens have -3 charge and Phosphorus has +5, yes?

Offline chenbeier

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Re: Phosphate has -3 charge. Why and how?
« Reply #3 on: October 07, 2018, 09:57:28 AM »
Yes, if you have the partner ions included, like  Na3PO4. The charge is zero.

Offline mjc123

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Re: Phosphate has -3 charge. Why and how?
« Reply #4 on: October 08, 2018, 04:45:29 AM »
Quote
So the overall charge is still 0 yes? Only oxygens have -3 charge and Phosphorus has +5, yes?
That doesn't give an overall charge of 0, does it? Formally it can be regarded as P5+ surrounded by 4 x O2- (though it is not really ionic like that), with an overall charge of +5 -8 = -3.
As chenbeier says, a phosphate compound, like Na3PO4, is electrically neutral.

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