Calcium

Definition

Calcium is a chemical element with the symbol Ca and atomic number 20, classified as an alkaline earth metal. It plays a vital role in various biological processes and is essential for the formation of bones and teeth in living organisms. Calcium also has important reactions with other elements and compounds, showcasing its reactivity and forming numerous compounds that are significant in both nature and industry.

5 Must Know Facts For Your Next Test

1. Calcium is the fifth most abundant element in the universe by mass and the third most abundant metal, following aluminum and iron.
2. It reacts vigorously with water to produce hydrogen gas and calcium hydroxide, showcasing its reactivity among alkaline earth metals.
3. Calcium ions play crucial roles in muscle contraction, neurotransmitter release, and blood coagulation in biological systems.
4. Common dietary sources of calcium include dairy products, leafy green vegetables, nuts, and fortified foods.
5. Calcium forms various compounds such as calcium sulfate (used in plaster) and calcium chloride (used as a de-icing agent), which are important in industrial applications.

Review Questions

• Discuss the role of calcium in biological systems and how it contributes to essential bodily functions.
  • Calcium is essential for several vital processes in biological systems. It aids in muscle contraction by interacting with proteins like troponin and tropomyosin, allowing muscle fibers to contract. Additionally, calcium ions are involved in neurotransmitter release at synapses, enabling communication between nerve cells. Furthermore, calcium is critical for blood coagulation, where it acts as a cofactor for several enzymes involved in the clotting process.
• Analyze how the reactivity of calcium with water compares to that of other alkaline earth metals.
  • Calcium's reactivity with water is significant but varies when compared to other alkaline earth metals. While magnesium reacts slowly with water at room temperature, calcium reacts more vigorously to produce hydrogen gas and calcium hydroxide. This pattern of increasing reactivity continues down the group; for example, strontium and barium react even more explosively with water. This trend is linked to the increasing atomic size and decreasing ionization energy of the metals as you move down the group.
• Evaluate the importance of calcium carbonate in both natural ecosystems and human industry.
  • Calcium carbonate plays a crucial role in both natural ecosystems and various industrial applications. In nature, it forms sedimentary rocks like limestone, contributes to the structure of shells in marine organisms, and acts as a buffer system in aquatic environments. In human industry, calcium carbonate is widely used in construction materials such as cement and concrete, as well as in agriculture to improve soil quality. Its versatility makes it an indispensable resource for sustainable development.

Related terms

Alkaline Earth Metals: A group of elements in Group 2 of the periodic table, which includes beryllium, magnesium, calcium, strontium, barium, and radium; known for their reactivity and tendency to form basic oxides.

Calcium Carbonate: A common compound formed from calcium, carbon, and oxygen, often found in rocks and used in various industries, including construction and agriculture.

Hydroxylapatite: A mineral form of calcium apatite that is a primary component of bone and teeth; its structure provides strength and rigidity to these biological tissues.