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eternallyboreduser

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What does this q even want me to do? Do they just mean write out the valencies of each element between198C7EF1-9B2E-498A-B84F-40E8777867C1.jpeg Sodium and argon?
 

wizzkids

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It seems like a perfectly good question. There are eight elements in the third period. They each have very different electronegativities, some are electron donors (Na, Mg, Al) and some are electron acceptors (P, S, Cl). Si is an interesting case to discuss. Then there is Ar which doesn't form compounds and you could call it valency 0.
valency.png
 

eternallyboreduser

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It seems like a perfectly good question. There are eight elements in the third period. They each have very different electronegativities, some are electron donors (Na, Mg, Al) and some are electron acceptors (P, S, Cl). Si is an interesting case to discuss. Then there is Ar which doesn't form compounds and you could call it valency 0.
View attachment 42747
Yeah ik but what does the q want me to do? Just list out the valencies or what?
 

Luukas.2

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question makes no sense lol why is it 4 marks
Yeah exactly wth do they even want me to compare theres nothing to compare for valencies
I think the observation implicit in these questions / comments is important... why is this worth 4 marks? Is it just a mistake, or an indication that something is being missed?

Start by considering the term "valency"... it is more than just the charges in @wizzkids' table, which tells us about ionic forms. I can use them to predict magnesium phosphide will be Mg3P2, for example, but what about the compounds of non-metals?

Then, notice that the period requested is not period 2, which is more chemically straight-forward, but period 3... how does this make a difference?

Period 3 non-metals have the ability to expand valence shells and violate the octet rule as the 3d sub-shell is accessible.

Now, think about the valency implications of phosphorous forming both PCl3 and PCl5.

What about sulfur forming H2S, SCl2, SOCl2, SO2, SO3, SF2, SF4, and SF6?

Or, chlorine forming Cl2O, Cl2O3, Cl2O5, and Cl2O7?

I can say that nitrogen has a valency of 3, but is that always true of phosphorous? Are there comparisons that I can make between period 3 and their counterpart period 2 elements, or comparisons with each other within period 3?

I think there is scope to say a lot in answer to this question, both about ionic and covalent compounds...
 

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