Question

Based on the following observations for 3 unidentified metals (Z, X, and D) and solutions of their metal cations (Zn+ and En+), rank the metals in terms of reducing agent strength, from lowest to highest.

-When metal X is placed in an aqueous solution of En+, a dark residue forms on the metal.

-When metal Z is placed in an aqueous solution of En+, the metals appearance does not change.

-When metal D is placed in an aqueous soltuion of Zn+, the metal appearance does not change.

-When metal X is placed in an aqueous solution of Zn+, a dark residue forms on the metal.

Weakest RA________,______,________,______Strongest RA

Answer 1

Forget the n and just go with + and we won't try to balance the electrons. (1) means statement 1; (2) means statement 2 etc. And note that Z ==> Z^+ means Z has lost electrons which means it is oxidized which means it is an reducing agent.
(1) So X is stronger than E.
X ==> X^+ + e
E ==> E^+ + e

(2) means metal Z is below metal E so now table looks like this.
X ==> X^+ + e
E ==> E^+ + e
Z ==> Z^+ + e

(3) means D is below Z. The table now becomes
X ==> X^+ + e
E ==> E^+ + e
Z ==> Z^+ + e
D ==> D^+ + e

(4) means X is above Z so the table under (3) is correct. The strongest reducing agent is at the top and the weakest at the bottom.Omit metal E from the final list.

If you wish to add the n to it all of the above would be written as in this example.
X ==>X^n+ + ne or
Z ==> Z^n+ + ne etc. but sticking that n (for number of electrons just confuses things.It is necessary IF you want to show a balanced equation.
I'm not convinced metal E is needed but it's listed in the question so I've included it.