Phosphate

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Algernon Jackson 2l
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Phosphate

Postby Algernon Jackson 2l » Sun Nov 15, 2020 8:52 pm

Why is phosphate an exception to the octet rule?

JoshMoore2B
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Re: Phosphate

Postby JoshMoore2B » Sun Nov 15, 2020 8:56 pm

Algernon Jackson 2l wrote:Why is phosphate an exception to the octet rule?


It isn't that phosphate itself is an exception to the octet rule, but rather that the phosphorus in the phosphate acts as an exception to the octet rule to create the compound. This is because the phosphorus has access to the 3d orbital, and so it can take on more bonds (in the case of phosphate, 5 instead of the 3 expected by its group) because it is able to store more than 8 electrons in its valence shell, which is called an expanded octet.

Thomas Vu 1A
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Re: Phosphate

Postby Thomas Vu 1A » Mon Nov 16, 2020 2:55 pm

Just to add on, any atom starting with period 3 and beyond (with the exception of Na+ and Mg I think) will be able to have an expanded octet because of access to that 3d orbital.

shevanti_kumar_1E
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Re: Phosphate

Postby shevanti_kumar_1E » Mon Nov 16, 2020 3:23 pm

Phosphate can have an expanded octet because it can accommodate more than 8 valence electrons. Atoms in periods 3 or greater have d orbitals in valence shell that can accommodate additional electrons. An example is phosphorus pentachloride (PCl5). In this molecule P has an expanded octet and bonds with 5 Cl.

rhettfarmer-3H
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Re: Phosphate

Postby rhettfarmer-3H » Sun Nov 22, 2020 11:34 pm

Phosphate can have an extended octet because it is the first row of p block before the introduction of the 3d block. Therefore, it is open to be used. Hence, that is why phosphorus and elements in the p block below the 3 p are able to open and sue the 3d block. Also, it is low energy so it's not too taxing for stability.

AlbertGu_2C
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Re: Phosphate

Postby AlbertGu_2C » Tue Nov 24, 2020 9:54 pm

Phosphate is in the 3p orbital, so it has access to the 3d orbital of electrons, so it can fill that shell to compensate.

Jasraj Parmar 3H
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Re: Phosphate

Postby Jasraj Parmar 3H » Tue Nov 24, 2020 10:56 pm

Phosphate is in period 3 so it can have an expanded octet and hold up to 18 electrons theoretically.

Gian Boco 2G
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Re: Phosphate

Postby Gian Boco 2G » Sun Nov 29, 2020 11:43 pm

Phosphate has access to the 3d state, which means it can add extra valence electrons


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