Problem 80 - Chemistry Matter and Change

Question

In each of the following pairs, which element will replace the other in a reaction? a. tin and sodium \(\quad \) c. lead and silver b. fluorine and iodine \(\quad \) d. copper and nickel

Step-by-Step Solution

Answer

In each pair, the element with higher reactivity will replace the other element in a reaction. Using the reactivity series, we have: a. Sodium (Na) will replace tin (Sn). b. Fluorine (F) will replace iodine (I). c. Lead (Pb) will replace silver (Ag). d. Nickel (Ni) will replace copper (Cu).

Step 1: Pair a: tin and sodium

Based on the reactivity series for metals, sodium (Na) is more reactive than tin (Sn), so sodium will replace tin in a reaction.

Step 2: Pair b: fluorine and iodine

According to the reactivity series for non-metals, fluorine (F) is more reactive than iodine (I), so fluorine will replace iodine in a reaction.

Step 3: Pair c: lead and silver

Referring to the reactivity series for metals, lead (Pb) is more reactive than silver (Ag), so lead will replace silver in a reaction.

Step 4: Pair d: copper and nickel

From the reactivity series for metals, nickel (Ni) is more reactive than copper (Cu), so nickel will replace copper in a reaction. We have now determined which element will replace the other in each given pair based on their reactivity rankings in the reactivity series.

Key Concepts

Metal Reactivity

Metal reactivity is a concept that describes how likely a metal is to participate in chemical reactions. The reactivity of metals is often represented using the reactivity series, which lists metals in order of increasing or decreasing reactivity. In this series, highly reactive metals like sodium (Na) and potassium (K) are placed at the top, while less reactive metals such as gold (Au) and platinum (Pt) are found at the bottom.
Understanding the reactivity series helps predict which metals can displace others from compounds. For instance, in the example pairs we examined, sodium (Na) being higher in the reactivity series, can replace tin (Sn), while lead (Pb) can replace silver (Ag), and nickel (Ni) can replace copper (Cu).

• The more reactive a metal, the more readily it loses electrons to form positive ions.
• Highly reactive metals can even react with water or oxygen at room temperature.

By learning the metal reactivity series, one can easily identify which metals will react more aggressively in various chemical scenarios.

Non-metal Reactivity

Non-metal reactivity is similar to metal reactivity, but focuses on elements that are not metals. Non-metals gain electrons during chemical reactions to form negative ions. Like metals, non-metals have their own reactivity series, with fluorine (F) being the most reactive.
This reactivity allows non-metals such as fluorine to replace less reactive non-metals like iodine (I) in compounds, making it a key factor in many chemical reactions.

• Non-metals like fluorine are strong oxidizing agents—they attract electrons.
• The reactivity decreases as you move down the group in the Periodic Table.

For common non-metals in reactions, always consider their position in the reactivity series to predict possible displacement reactions.

Element Replacement

Element replacement in reactions is a fascinating concept tied closely with the reactivity series. When we talk about element replacement, we're referring to a chemical reaction where a more reactive element displaces a less reactive one from a compound.
For example, in reactions involving sodium and tin, sodium will replace tin due to its higher reactivity. The same principle applies to fluorine and iodine, lead and silver, and nickel and copper.

• Element replacement reactions are often called single displacement or substitution reactions.
• These reactions can be used to extract metals from their ores or to synthesize different compounds.

Understanding element replacement allows chemists to predict the outcomes of chemical reactions efficiently.

Chemical Reactions

Chemical reactions are processes where substances interact to form new products. They are at the heart of chemistry, involving the breaking and making of bonds. Different types of reactions include synthesis, decomposition, single replacement, and double replacement.
The reactivity series plays a crucial role in predicting the feasibility and outcome of reactions, especially those involving element replacement. In single replacement reactions, knowledge of an element's reactivity can predict whether a reaction will occur.

• Reactants in a chemical reaction may include elements, compounds, or mixtures.
• The type and condition of a chemical reaction—such as temperature and concentration—affects its speed and product formation.

Grasping chemical reactions and how they work is essential for understanding both natural processes and industrial applications.