Contributor: Hannah Brooks. Lesson ID: 12909
If a sports team is not performing well, the coach might take a player out of the game and send in a stronger player. In the world of atoms, a stronger atom will replace another atom in a compound!
In a closely fought soccer match between the Red Tigers and the Green Thunderbirds, with the score tied 1-1 and only 10 minutes left, Coach Anderson made a surprising substitution. He took out star midfielder Sarah and put in Lily, a lesser-known player.
Lily's fresh energy and incredible speed disrupted the Thunderbirds' midfield. She intercepted passes, chased down loose balls, and inspired her teammates. The Tigers, who had been on the defensive all game, suddenly gained momentum.
In the 88th minute, Lily delivered a perfect cross, setting up a headed goal by Jake. The Tigers took a dramatic 2-1 lead and held on to win. Coach Anderson's bold substitution changed the game dynamic, proving that sometimes, surprises can lead to victory.
Coaches often substitute players in and out during games based on the skill set of each player.
Changing the team's composition can lead to a change in the score!
A chemical reaction in which elements replace one another in compounds is called a single-replacement reaction.
Single-replacement reactions follow this pattern.
A + BC → B + AC
A good example of a single-replacement reaction is the formation of sodium hydroxide: 2Na + 2HOH → 2NaOH + H2. Notice that the hydrogen is replaced with a sodium atom.
In a single-replacement reaction, the element that replaces another must be more reactive. That means it is more likely to bond with other elements.
Well, you can use the reactivity series to determine the reactivity of different elements.
Check out the Reactivity Series of metals.
In a single-replacement reaction, the replacement element must be more reactive than the element it is replacing.
For example, potassium can replace almost any other metal, while gold doesn't replace many metals. Remember that metals are cations or positively charged particles.
Cations can only replace cations, and anions can only replace anions.
If the replacement element is less reactive, the reaction will not run. The reaction equation would be A + BC → no reaction.
Single-replacement reactions run when one element works to replace another element held in a chemical bond. To break the existing bond, the replacement element must be more reactive.
The reactivity series helps you know if the reaction will run.
You write the equation yielding no reaction. Write a one-sentence summary of how the reactivity series is used in chemistry.
In the Got It? section, practice using the reactivity series to determine if the reaction runs.