Introduction
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- Zinc is a member of group IIb of the periodic table.
- Zinc has 30 electrons.
- The atomic number of zinc is 30 whereas its atomic mass is 65.
- The symbol of zinc is ‘Zn’.
Naming and History
Zinc got its name from the old German word “Zinke” which means pointed and spiky. This was because zinc has sharp, pointed crystals. And secondly, the German word ‘zin’ means tin.
Zinc is known to humans since ancient times and was used to make alloys such as brass; a mixture of copper and zinc. The smelting of zinc began in the early 1200s. It was first recognized as a metal at Zawar in Rajasthan.
A Flemish metallurgist in 1668, first extracted metallic zinc from zinc oxide. But Europe claimed that zinc was first identified by a German chemist named Andreas Marggraf in 1746.
Occurrence of Zinc
Zinc is the 24th most abundant element on Earth’s crust but in its pure elemental form, it does not exist. Zinc can be obtained from minerals such as smithsonite, wurtzite, hemimorphite, sphalerite, etc. Sphalerite is the major source of zinc as it contains 60% of zinc.
These minerals are widely distributed throughout the world. Major suppliers are Canada, Russia, Australia, Peru, etc.
Properties of Zinc
Zinc is a lustrous, crystalline, brittle, bluish-silver, or whitish metal. When comes in contact with air, it tarnishes. Zinc is a fairly reactive element and can react with other elements to form compounds such as oxygen to form oxides of zinc.
Zinc reacts with dilute acids and liberates hydrogen. At low temperatures, zinc is brittle but at a temperature above 100 ᵒC, it is malleable and used to make sheets of it. It does not corrode easily that’s why use to coat iron and the process called galvanization.
Zinc is a good conductor of electricity. It produces bright bluish-green flame with oxides of zinc on burning. Zins is solid at room temperature. The melting point of zinc is 419.53°C and its boiling point is 907°C. The density of zinc is 7.134 grams per cubic centimeter.
Zinc in Biological Systems
Zinc is an essential element in almost all life forms. In humans, it is present as a trace element and is necessary for the proper functioning of enzymes. It forms active sites of almost 20 enzymes.
Zinc activates the enzymes needed for the synthesis of proteins. It also plays role in the formation of chlorophyll. It helps plants to survive in cold conditions.
Zinc is not a toxic element, but fresh zinc oxide if inhaled, can cause a disorder called zinc chills or oxide shakes.
Uses of Zinc
The major use of zinc is galvanizing. It is used to coat iron to prevent it from rusting and then this galvanized iron or steel is used in making suspension bridges, car bodies, etc.
- In electric batteries, zinc is sometimes used as a negative plate.
- Zinc is used to make alloys. Brass, an important alloy of zinc is widely used in making coins, cookware, and other items.
- Zinc oxide, as a white pigment is used in paints.
- Used as an activator in the rubber industry.
- Zinc sulfide converts ultraviolet light to visible light so used in fluorescent bulbs.
- Zinc chloride serves as a fire-retardant chemical and is mixed in wood or timber.
- Zinc has a wide range of uses in pharmaceutics, cosmetics, soap, and the plastic industry. Zinc is used to make sunscreens as it forms barriers on the skin to avoid ultraviolet rays.
- Zinc is used in making anti-aging medicines as it contains antioxidants to prevent premature aging.
- It is used in the roofing of buildings.
Isotopes of Zinc
There are almost 25 isotopes whose half-lives are known to date, mass ranging from 57 to 83. There are 5 naturally occurring isotopes. Zinc- 64 is the most abundant one with a percentage of 48.
MCQs
- What is the atomic number of zinc?
- A) 24
- B) 30
- C) 65
- D) 7.134
- Answer: B
- From where did zinc get its name?
- A) Old English word
- B) Latin word “Zincus”
- C) Old German word “Zinke”
- D) Greek word “Zin”
- Answer: C
- Who was the first to extract metallic zinc from zinc oxide?
- A) Andreas Marggraf
- B) Flemish metallurgist
- C) A German chemist
- D) A metallurgist from Rajasthan
- Answer: B
- What is the major source of zinc?
- A) Smithsonite
- B) Wurtzite
- C) Hemimorphite
- D) Sphalerite
- Answer: D
- What happens when zinc comes in contact with air?
- A) It tarnishes
- B) It melts
- C) It evaporates
- D) It remains unchanged
- Answer: A
- What is the major use of zinc in the galvanizing process?
- A) To make it conductive
- B) To prevent rusting
- C) To enhance its shine
- D) To make it malleable
- Answer: B
- How is zinc used in the electric battery industry?
- A) As a cathode
- B) As a negative plate
- C) As an anode
- D) As an electrolyte
- Answer: B
- What is the primary function of zinc oxide in paints?
- A) To add color
- B) To prevent corrosion
- C) To act as a flame retardant
- D) To serve as a white pigment
- Answer: D
- Which industry uses zinc sulfide in fluorescent bulbs?
- A) Pharmaceutical
- B) Cosmetics
- C) Rubber
- D) Lighting
- Answer: D
- What is zinc chloride commonly used for?
- A) As a food preservative
- B) As a fire-retardant chemical
- C) As a fertilizer
- D) As a cleaning agent
- Answer: B
- How is zinc utilized in the cosmetic industry?
- A) In making sunscreens
- B) In producing fragrances
- C) In manufacturing lipstick
- D) In making hair dyes
- Answer: A
- What role does zinc play in biological systems?
- A) Enhancing vision
- B) Activating enzymes
- C) Regulating body temperature
- D) Strengthening bones
- Answer: B
- Which isotopic form of zinc is the most abundant?
- A) Zinc-64
- B) Zinc-57
- C) Zinc-83
- D) Zinc-30
- Answer: A
- How many naturally occurring isotopes of zinc are there?
- A) 10
- B) 5
- C) 25
- D) 20
- Answer: B
- What disorder can be caused by inhaling fresh zinc oxide?
- A) Zinc toxicity
- B) Zinc deficiency
- C) Zinc chills or oxide shakes
- D) Zinc poisoning
- Answer: C
- What is the melting point of zinc?
- A) 777°C
- B) 1000°C
- C) 419.53°C
- D) 1382°C
- Answer: C
- Which element is commonly alloyed with zinc to produce brass?
- A) Nickel
- B) Copper
- C) Aluminum
- D) Iron
- Answer: B
- What property of zinc makes it suitable for use in suspension bridges?
- A) Low density
- B) High strength
- C) Resistance to corrosion
- D) Ductility
- Answer: C
- In which industry is zinc oxide used as an activator?
- A) Rubber
- B) Pharmaceutical
- C) Paint
- D) Plastic
- Answer: A
- What temperature does zinc become malleable?
- A) Below 0°C
- B) Above 100°C
- C) Above 777°C
- D) Below 100°C
- Answer: B
Summary
The tutorial on zinc goes into various aspects of this essential element, ranging from its occurrence and properties to its biological significance, uses, and isotopic composition.
- Introduction:
- Provides fundamental information about zinc, including its atomic number, atomic mass, and its position in the periodic table.
- Naming and History:
- Traces the historical background of zinc, its naming origin from the old German word “Zinke,” and its usage in ancient times for making alloys like brass.
- Occurrence of Zinc:
- Discusses the abundance of zinc in the Earth’s crust and its extraction from minerals such as sphalerite, highlighting major global suppliers.
- Properties of Zinc:
- Explores the physical and chemical properties of zinc, including its lustrous appearance, reactivity, and utility in galvanization.
- Zinc in Biological Systems:
- Examines the essential role of zinc in biological systems, particularly in enzyme function, protein synthesis, and chlorophyll formation, while cautioning against potential inhalation hazards.
- Uses of Zinc:
- Details the diverse applications of zinc, from galvanizing iron to prevent rusting, to its use in alloys, paints, rubber industry, and fluorescent bulbs, as well as its role in pharmaceuticals, cosmetics, and sunscreens.
- Isotopes of Zinc:
- Provides insights into the isotopic composition of zinc, highlighting the natural abundance of isotopes and their significance in various scientific studies.
This comprehensive summary encapsulates the key points covered in the tutorial, offering a holistic understanding of zinc and its multifaceted roles in science, industry, and biology.