Alkaline earth metals

Definition

Alkaline earth metals are a group of elements found in Group 2 of the periodic table, consisting of beryllium, magnesium, calcium, strontium, barium, and radium. These metals are characterized by their shiny appearance, low density, and relatively low melting points. They play significant roles in various chemical reactions and biological processes, and their properties can be linked to their position in the periodic table and atomic structure.

5 Must Know Facts For Your Next Test

1. Alkaline earth metals typically have two valence electrons, making them highly reactive, especially with water and halogens.
2. Calcium is one of the most abundant alkaline earth metals in the Earth's crust and is essential for biological functions such as muscle contraction and nerve signaling.
3. These metals tend to form +2 cations by losing their two outermost electrons during chemical reactions.
4. Beryllium is unique among alkaline earth metals due to its relatively high melting point and its tendency to form covalent rather than ionic compounds.
5. Alkaline earth metals react with water to produce hydroxides and hydrogen gas, with reactivity increasing down the group from beryllium to radium.

Review Questions

• How do the physical and chemical properties of alkaline earth metals change as you move down the group in the periodic table?
  • As you move down the group of alkaline earth metals in the periodic table, both physical and chemical properties change significantly. The atomic size increases due to additional electron shells, which leads to a decrease in ionization energy and electronegativity. Consequently, reactivity increases down the group; for example, magnesium reacts moderately with water while barium reacts vigorously. Additionally, melting points generally decrease as you go down the group.
• Compare the reactivity of alkaline earth metals with that of alkali metals and explain why these trends exist.
  • Alkaline earth metals are less reactive than alkali metals because they have a higher ionization energy due to their greater nuclear charge. While both groups readily lose electrons to form cations, alkali metals (Group 1) have only one valence electron that they lose easily. In contrast, alkaline earth metals must lose two valence electrons, which requires more energy. This difference in electron configuration leads to distinct reactivity patterns: alkali metals react more vigorously with water than alkaline earth metals.
• Evaluate the significance of alkaline earth metals in biological systems and industrial applications.
  • Alkaline earth metals play crucial roles in biological systems and various industrial applications. For instance, calcium is vital for bone health, muscle function, and neurotransmission in living organisms. In industry, magnesium is widely used as a lightweight structural material and in manufacturing processes such as die-casting. Furthermore, compounds like calcium carbonate are significant in construction and environmental applications. Understanding these elements' roles highlights their importance not only in chemistry but also in health and technology.

Related terms

Group 2 Elements: The set of elements in the second column of the periodic table, known for having two electrons in their outermost shell.

Electronegativity: A measure of an atom's ability to attract and hold onto electrons; alkaline earth metals have low electronegativity compared to other elements.

Ionic Compounds: Compounds formed through the transfer of electrons from metals to non-metals, commonly produced by alkaline earth metals when they react with halogens or oxygen.