1
$\begingroup$

If an element $\ce{X}$ forms the highest oxide of the formula $\ce{XO3}$, then it belongs to group:
A) 14
B) 15
C) 16
D) 17

How is an oxidation number of an element related to its group?

I tried comparing $\ce{X}$ with $\ce{N}$-, $\ce{S}$-, $\ce{As}$-compounds, but all 3 come in the form $\ce{XO3}$ ($\ce{NO3}$, $\ce{SO3}$, $\ce{AsO3}$), so I can't guess the group number.

$\endgroup$
  • 2
    $\begingroup$ Read the text more carefully. It says that the "highest oxide" has the formula $\ce{XO_3}$, while the 3 possibilities you mention contain only one oxide and 2 oxyanions. $\endgroup$ – Saghe Jul 13 '14 at 11:45
  • $\begingroup$ Isn't $\ce{SO3}$ the highest oxide of $\ce{S}$? $\endgroup$ – Silvio Levy Jul 25 '14 at 20:20
  • $\begingroup$ actually SO4- is the highest oxide. Oxide means that the oxygen is more electronegative, not necessarily that the compound is also neutral. $\endgroup$ – Caters Aug 16 '14 at 21:17
4
$\begingroup$

For main group elements (groups 1, 2, 13-18), the highest possible oxidation state $O_\text{max}$ is given by the group number $G$ (for groups 1 and 2) or by the group number - 10 (for the rest): $$ O_\text{max} = \begin{cases} G &\text{if } G \in \{1,2\} \\ G - 10 &\text{if } 13 \leq G \leq 18 \end{cases} $$

This means that for your compound $\ce{\stackrel{VI}{X}O3}$, so with the oxidation state VI, the corresponding group would be group 16.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.