another chem question

[arpitpatel86]

8. Iron reacts with element X to form the compounds FeX
and Fe​

​

3X2. When copper reacts with element X, the
expected compound(s) should be
A. CuX and Cu3X2.
B. Cu2X and Cu6X.
C. Cu3X only.
D. CuX2 only.​

E. Cu3X and Cu3X2.

ANSWRE IS E
Iron forms the +3 or the +2 ion: Fe​

​

3+ (ferric) and Fe2+ (ferrous). The fact that it reacts with X to form FeX and Fe3X2​

suggests that X forms an anion with a –3 charge. X​

​

3– reacts with the ferric ion to form FeX, since both have a –3 charge,
but reacts with the ferrous ion to form Fe3X2 to balance the charge. Copper usually forms either the +1 or the +2 ion.
When the former reacts with X, then, there must be three Cu+ ions to balance the charge, resulting in Cu3X. When the​

latter reacts with X, it does so in the same way that the ferrous ion does, forming Cu3X2.

makes sense but i still dont know how to calculate the charges for transition metals...how are we supp to know that copper has a plus 1 and plus 2 charge.....how do we not know if it only has one of those or multiple charges?

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[dentalplan]

8. Iron reacts with element X to form the compounds FeX​

and Fe3X2. When copper reacts with element X, the
expected compound(s) should be
A. CuX and Cu3X2.
B. Cu2X and Cu6X.
C. Cu3X only.
D. CuX2 only.​

E. Cu3X and Cu3X2.

ANSWRE IS E​

Iron forms the +3 or the +2 ion: Fe

3+ (ferric) and Fe2+ (ferrous). The fact that it reacts with X to form FeX and Fe3X2

suggests that X forms an anion with a –3 charge. X​

​

3– reacts with the ferric ion to form FeX, since both have a –3 charge,

but reacts with the ferrous ion to form Fe3X2 to balance the charge. Copper usually forms either the +1 or the +2 ion.
When the former reacts with X, then, there must be three Cu+ ions to balance the charge, resulting in Cu3X. When the​

latter reacts with X, it does so in the same way that the ferrous ion does, forming Cu3X2.

makes sense but i still dont know how to calculate the charges for transition metals...how are we supp to know that copper has a plus 1 and plus 2 charge.....how do we not know if it only has one of those or multiple charges?​

i see what you're saying...r u sure they didn't give the oxidation states to use for iron and copper? If they didn't, i think u were just supposed to assume the most popular oxidation states.

iron actually can be +1, +2, +3, +4, +5, and +6! copper i think can be +1, +2, +3, and +4. However, the most popular states are +2 and +3 for iron and +1 and +2 for copper. I agree this is a hard question cuz u have to know a little bit about oxidation state physical chemistry.

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