key term - High Reactivity

Definition

High reactivity refers to the tendency of certain elements, particularly alkali and alkaline earth metals, to readily engage in chemical reactions with other substances. This trait is primarily due to their electronic configuration, where they possess one or two electrons in their outer shell, making it easier for them to lose these electrons and form bonds. These metals are known for their vigorous reactions, often resulting in the release of energy and the formation of stable compounds.

5 Must Know Facts For Your Next Test

1. Alkali metals are highly reactive and can spontaneously ignite when exposed to air or moisture.
2. Alkaline earth metals react vigorously with water to form hydroxides and release hydrogen gas.
3. Reactivity increases down the group for both alkali and alkaline earth metals due to decreasing ionization energy.
4. When reacting with halogens, alkali metals form ionic compounds known as halides that are typically white solids.
5. The high reactivity of these metals makes them difficult to find in nature; they are often stored under oil to prevent reactions with moisture or oxygen.

Review Questions

• How does the electronic configuration of alkali and alkaline earth metals contribute to their high reactivity?
  • The electronic configuration of alkali metals shows that they have one electron in their outermost shell, while alkaline earth metals have two. This makes it easy for alkali metals to lose their single outer electron and form positive ions. Similarly, alkaline earth metals can lose their two outer electrons. The lower ionization energy required for these processes enhances their ability to react quickly with other elements.
• Evaluate the differences in reactivity between alkali and alkaline earth metals when they come into contact with water.
  • Alkali metals react more violently with water than alkaline earth metals. For example, sodium reacts explosively with water, producing sodium hydroxide and hydrogen gas. In contrast, alkaline earth metals like calcium also react with water but typically at a slower rate. The strength of the reaction is influenced by the number of valence electrons; alkali metals require less energy to lose one electron compared to alkaline earth metals losing two.
• Synthesize a general equation for the reaction of an alkali metal with a halogen and discuss how this illustrates their high reactivity.
  • The general equation for an alkali metal M reacting with a halogen X can be represented as: $$2M + X_2 \rightarrow 2MX$$. This reaction demonstrates high reactivity because it shows how easily alkali metals combine with halogens to form ionic compounds. The formation of a stable ionic bond releases significant energy, indicating that these metals are driven by a strong tendency to achieve a more stable electron configuration through such reactions.

Related terms

Alkali Metals: The group of elements in Group 1 of the periodic table, including lithium, sodium, potassium, rubidium, cesium, and francium, characterized by their single valence electron and high reactivity.

Alkaline Earth Metals:

The group of elements in Group 2 of the periodic table, including beryllium, magnesium, calcium, strontium, barium, and radium, known for having two valence electrons and also exhibiting high reactivity.

Oxidation-Reduction Reaction: A type of chemical reaction involving the transfer of electrons between two species, crucial for understanding how highly reactive metals interact with nonmetals.