[Gman]

Here are a few problems, to which believe I know the answers to.  However when I type the answer in the box, it says its incorrect.  I might be completely wrong in the way I went about answering them.

For each of the following four sets of conditions, enter the formula of the simple ionic compound that could form from the elements X and Z. Give the cationic element first and the anionic element second.
e.g. X3Z5 (if X is the cation) -- subscripts are inferred.
(Coefficients of "1" are omitted -- as in NaCl)


X has 7 valence electrons and Z has 3 valence electrons:
   (my answer) X3Z7
X has 1 valence electron and Z has 6 valence electrons:
   (my answer) X6Z
X has 2 valence electrons and Z has 7 valence electrons:
   (my answer) X7Z2
X has 3 valence electrons and Z has 5 valence electrons:
   (my answer) X5Z3

I would appreciate it if you could give me some feedback.

[Yggdrasil]

Ideally, an ion would like to have 8 valence electrons.  It can achieve this stable state by either gaining enough electrons to let it have 8 valence electrons or losing all of its valence electrons.

For the first question, X has 7 valence electrons and would therfore want to gain another electron.  Z wants to lose 3 electrons.  Since Z will give up three electrons, it will take 3 X atoms to take up those electrons, giving the formula X₃Z.

Now, try the other three.

[AngelShare]

This would go along with one of my problems wouldn't it? "Why do elements react to form compounds?" Because they want to achieve that structure, have their outer shell full with 8 electrons?

[Mitch]

"Why do elements react to form compounds?" Because they want to achieve that structure, have their outer shell full with 8 electrons?

Thats a very messy question. We tell high schoolers these things but the truth is far different. 99% of reagents already have a full valence, so why would they react? Can you actually think of a reagent that doesn't have a complete valence?

[AngelShare]

Wow...I, uh...*Shakes head confused* I am a highschooler so I think I may just stick with the simple answer before pushing forward with that...better walk before I run.