Why is a iron ion attracted to a sulfide ion but not not to a zinc ion?
Iron (Fe) and zinc (Zn) are both transition metals that can form positive ions (Fe2+ and Zn2+) due to their tendency to lose electrons. Sulfur (S) is a non-metal that can gain electrons to form negative sulfide ions (S2-).
When an iron ion (Fe2+) and a sulfide ion (S2-) come close to each other, an ionic bond can form between them. This is because the iron ion has a positive charge and the sulfide ion has a negative charge. Opposite charges attract each other, resulting in the formation of an ionic bond.
On the other hand, zinc ions (Zn2+) do not form a strong attraction with sulfide ions. This is because zinc ions have a smaller positive charge density compared to iron ions. The charge density refers to the concentration of electric charge within a given volume. In other words, the positive charge of the zinc ion is spread over a larger space, making it less effective at attracting the negatively charged sulfide ion.
To summarize, the attraction between an iron ion and a sulfide ion is stronger than the attraction between a zinc ion and a sulfide ion due to the difference in charge density. The iron ion has a higher positive charge density, allowing it to form a stronger ionic bond with the sulfide ion.