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Zinc (Zn)

QUICK REFERENCE

  • Symbol: Zn
  • Atomic Number: 30
  • Atomic Weight: 65.38
  • Element Classification: Transition Metal, though often considered a post-transition metal due to its properties
  • Discovered By: Known to the ancients in alloy form; isolated in India by 1300 AD
  • Discovery Date: Isolated in Europe by Andreas Marggraf in 1746
  • Name Origin: German: ‘Zink’
  • Density(g/cc): 7.134
  • Melting Point: 419.53°C
  • Boiling Point: 907°C
  • Appearance: Bluish-silver, bright, and lustrous metal
  • Atomic Radius(pm): 134

Discovery

While zinc compounds were used for centuries before it was recognized as a distinct element, metallic zinc was first isolated in India by the 14th century and later in Europe by Andreas Marggraf, a German chemist, in 1746. Marggraf identified zinc as a separate metal by heating calamine (zinc carbonate) with charcoal, producing metallic zinc. The term “zinc” comes from the German word ‘Zink’, which might have been derived from the Persian word ‘sing’, meaning stone.

Relation to Other Elements

Zinc is sometimes considered a transition metal and sometimes a post-transition metal, owing to its properties which are somewhat intermediate between those of both groups. It is less reactive than metals in groups 1 and 2 but forms a protective layer of oxide on its surface, which prevents further corrosion. Zinc commonly exhibits a +2 oxidation state in its compounds, which include various important zinc salts used in industry and medicine.

Natural Occurrence

Zinc is the 24th most abundant element in the Earth’s crust. It does not occur freely in nature but is found in minerals such as sphalerite (zinc sulfide, ZnS), the most important zinc ore. Other sources include smithsonite (ZnCO₃), hemimorphite (Zn₄Si₂O₇(OH)₂·H₂O), and franklinite ((Zn,Fe,Mn)(Fe,Mn)₂O₄). Large deposits of zinc ore are found in China, Australia, and the United States.

Uses

Zinc has a variety of uses due to its versatile properties:

  • Galvanization: The most common use of zinc is in galvanizing iron and steel to prevent rust. This process involves coating the steel with a thin layer of zinc.
  • Alloys: Zinc is used to form alloys with other metals, such as brass (copper and zinc), which is used in musical instruments, hardware, and fixtures.
  • Batteries: Zinc is a key component in alkaline batteries, zinc-carbon batteries, and zinc-air batteries.
  • Medicine: Zinc compounds, like zinc oxide, are used in ointments to treat skin conditions. Zinc is also an essential mineral necessary for human health, playing a role in immune function, wound healing, and protein synthesis.
  • Agriculture: Zinc sulfate is used as a dietary supplement in animal feeds and as a fertilizer to correct zinc deficiency in crops.

Zinc’s discovery and utilization have significantly impacted various industrial processes, technology, and healthcare. Its role in galvanization has made it critical in extending the life span of steel structures, while its biological importance ensures it remains a vital element in nutrition and medicine.

Copper (Cu)

Gallium (Ga)