Alkaline earth metals

Definition

Alkaline earth metals are a group of six elements in the second column of the periodic table, known for their characteristic properties and reactivity. This group includes beryllium, magnesium, calcium, strontium, barium, and radium. They play an important role in various chemical reactions and have distinct trends in atomic properties such as ionization energy, atomic radius, and electronegativity.

5 Must Know Facts For Your Next Test

1. Alkaline earth metals are characterized by having two electrons in their outermost shell, which they readily lose to form +2 ions.
2. These metals have low densities and melting points compared to most other metals, with the melting point decreasing as you move down the group.
3. Reactivity increases down the group; for example, magnesium reacts with water at higher temperatures, while barium reacts readily with cold water.
4. Calcium plays a crucial role in biological systems, being essential for bone formation and muscle function in living organisms.
5. Most alkaline earth metals react with oxygen to form metal oxides, which exhibit ionic bonding characteristics.

Review Questions

• How does the reactivity of alkaline earth metals change as you move down the group in the periodic table?
  • As you move down the alkaline earth metal group from beryllium to radium, reactivity increases significantly. This is primarily due to the increasing atomic radius and decreasing ionization energy, which makes it easier for these elements to lose their two outermost electrons. For example, while beryllium is relatively unreactive with water, calcium reacts vigorously and barium reacts explosively with water.
• Compare and contrast alkaline earth metals with alkali metals in terms of their chemical properties and trends.
  • Alkaline earth metals differ from alkali metals primarily in their reactivity and ionization characteristics. While both groups lose electrons to form positive ions, alkali metals have a single electron in their outer shell, making them more reactive than alkaline earth metals, which have two. Additionally, alkaline earth metals generally have higher melting points and densities than alkali metals. As a result, alkaline earth metals tend to be less reactive than alkali metals but still show significant reactivity, especially as you move down the group.
• Evaluate the significance of alkaline earth metals in both industrial applications and biological systems.
  • Alkaline earth metals are vital both industrially and biologically. In industry, they are used in various applications such as alloys (magnesium), fireworks (strontium), and pharmaceuticals (calcium). Biologically, calcium is crucial for living organisms; it contributes to bone structure and muscle contraction. The importance of these elements highlights not only their chemical properties but also their critical roles across different sectors, showcasing their versatility and necessity in everyday life.

Related terms

alkali metals: Alkali metals are the elements found in the first column of the periodic table, known for their high reactivity and tendency to lose one electron to form positive ions.

metalloids: Metalloids are elements that have properties of both metals and nonmetals, often found along the dividing line between metals and nonmetals on the periodic table.

periodicity: Periodicity refers to the recurring trends that are observed in the properties of elements across different periods of the periodic table.