Magnesium: Element Overview

Basic Information

• Symbol: Mg
• Atomic Number: 12
• Atomic Weight: 24.305 u
• Element Category: Alkaline earth metal
• Group: 2
• Period: 3

Physical Properties

• Phase at Room Temperature: Solid
• Melting Point: 650 °C (1202 °F)
• Boiling Point: 1091 °C (1994 °F)
• Density: 1.738 g/cm³ at 20 °C
• Color: Silvery-white

Chemical Properties

• Electronegativity: 1.31 (Pauling scale)
• Ionization Energies:
  • First: 737.7 kJ/mol
  • Second: 1450.7 kJ/mol
  • Third: 7732.7 kJ/mol

Isotopes

• Stable Isotopes: Magnesium has three stable isotopes: Mg-24, Mg-25, and Mg-26.
  • Mg-24: 78.99%
  • Mg-25: 10.00%
  • Mg-26: 11.01%

Occurrence and Production

• Natural Abundance: Magnesium is the eighth most abundant element in the Earth’s crust and is also abundant in seawater.
• Sources: Found in minerals like magnesite, dolomite, and carnallite.
• Production: Produced primarily by the electrolysis of magnesium chloride or by the thermal reduction of magnesium oxide with silicon.

Uses and Applications

• Alloys: Magnesium is used in alloys to improve the strength and lightness of materials, especially in the aerospace and automotive industries.
• Construction: Used in the manufacture of lightweight, high-strength materials.
• Medical: Magnesium compounds like magnesium hydroxide (milk of magnesia) are used as antacids and laxatives. Magnesium sulfate (Epsom salt) is used to treat muscle soreness.
• Electronics: Used in the production of electronics, including mobile phones and laptops.
• Chemical Industry: Used as a reducing agent in the production of metals like titanium and uranium.
• Photography and Pyrotechnics: Magnesium burns with a bright white light, making it useful in flares, fireworks, and photographic flashbulbs.

Safety and Precautions

• Reactivity: Magnesium is highly reactive, especially when powdered or in thin strips, and can burn with a bright white flame.
• Handling: Should be handled with care to prevent ignition. Fire involving magnesium should not be extinguished with water, as it can produce hydrogen gas and cause explosions.
• Biological Role: Essential for all cellular life, playing a crucial role in over 300 enzymatic reactions in the human body, including energy production and DNA synthesis.

Historical Background

• Discovery: Recognized as an element in 1755 by Joseph Black. Isolated by Sir Humphry Davy in 1808.
• Naming: The name “Magnesium” comes from the Greek district Magnesia in Thessaly, where magnesite was first found.

Interesting Facts

• Biological Importance: Magnesium is the central atom in the chlorophyll molecule, essential for photosynthesis in plants.
• Lightweight Metal: Magnesium is the lightest structural metal, being 33% lighter than aluminum.
• Magnesium in Water: Contributes to the hardness of water, especially in regions with high mineral content.

Summary

Magnesium is an alkaline earth metal known for its lightness, strength, and reactivity. It plays a vital role in the construction, aerospace, automotive, medical, and electronics industries. Biologically, it is essential for numerous cellular processes and is abundant in the Earth’s crust and seawater. Discovered in the 18th century and isolated in the early 19th century, magnesium continues to be a crucial element in both industrial applications and biological functions.