Introduction
Manganese is a transition metal in group VII b. Manganese has 25 electrons. Its atomic number is 25 whereas its atomic mass is 54. The symbol of Manganese is ‘Mn’.
Naming and History
The name of manganese is thought to have two routes of origin. Either it is derived from the Latin word “magnes”; a word for the magnet. Or it is from “magnesia nigra” which means black magnesium oxide.
The history of manganese is dated to pre-historic cave painters in the Lascaux region around 30,000 years ago. They used it in the form of black ore.
The work on manganese started in the 18th century. In 1740, glass technologist in Berlin, Johann Heinrich Pott studied manganese chemically and suggested that it was not iron as assumed before. He made the strongest oxidizing agent potassium per magnate.
In 1771, a student at Vienna stated in his paper the method of production of manganese metal. In 1774, Swedish chemist Johan Gottlieb was the first person who isolated manganese from its black ore pyrolusite.
Occurrence of Manganese
Manganese does not exist as a free element in nature. It occurs in oxides and hydrides. Manganese exists in minerals. The major manganese-containing mineral is pyrolusite. Other manganese-containing minerals are bixbyite, manganite, rhodochrosite, and rhodonite.
The major miner and suppliers of Manganese to the world are Georgia, Russia, South Africa, Ukraine, and Australia.
Properties of Manganese
In pure form, manganese is hard, a brittle pinkish, whitish-grey metal that is highly active. It is easily oxidized. The amazing fact is, it is not a magnet. On heating, it oxidizes to manganese oxides. When comes in contact with air, it tarnishes.
The melting point of manganese is 1246°C. Its boiling point is 2061°C. It has a density of 7.3 grams per cubic centimeter and exists as a solid at room temperature.
Manganese in Biological Systems
Manganese is an important bio element needed by all types of life. Although it is present in trace amounts but required by enzymes. It acts as a cofactor for enzymes. In plants, the enzyme for converting water molecules into oxygen has four atoms of manganese.
In manganese deficient soils, it is added through fertilizers. It is provided as a supplement to grazing animals. In humans, they are part of many enzymes. It strengthens the bones. Without it, bones will become spongier and break easily. It is also required for the absorption of vitamin B1.
High amounts of manganese are highly toxic. Long-term exposure to manganese such as in miners of manganese can cause a medical condition called manganism. Its symptoms are like Parkinson’s disease.
Uses of Manganese
Manganese is mainly (around 90%) used in making alloys for example steel and iron production.
On mixing with aluminum, manganese is widely demanded and used in the production of stainless steel.
Manganese dioxide the most abundant compound of manganese is used as filler in dry cell batteries.
The compound manganese dioxide is also used as a drying agent in black paints.
To reduce engine knocking and increase octane number, organo-manganese compounds are used.
Its aluminum alloys are corrosive resistant so are used in the production of soft drink cans.
Isotopes of Manganese
The known isotopes of manganese are 21 whose mass ranges from 46 to 66. The only stable isotope of manganese in nature is Manganese- 55.
MCQs about Manganese Element
- What is the group number of manganese in the periodic table?
- A) IV b
- B) V b
- C) VI b
- D) VII b
- Answer: D
- How many electrons does manganese have?
- A) 20
- B) 25
- C) 30
- D) 35
- Answer: B
- What is the atomic number of manganese?
- A) 20
- B) 25
- C) 30
- D) 35
- Answer: B
- What is the atomic mass of manganese?
- A) 44
- B) 54
- C) 64
- D) 74
- Answer: B
- What is the symbol for manganese?
- A) Mg
- B) Mn
- C) Ma
- D) Mo
- Answer: B
- What are the two possible origins of the name “manganese”?
- A) Magnet and Magnesium
- B) Magnesium and Magnesia
- C) Magnesia nigra and Magnet
- D) Magnesia and Magnetism
- Answer: C
- When did the use of manganese in prehistoric cave paintings date back to?
- A) 5,000 years ago
- B) 15,000 years ago
- C) 25,000 years ago
- D) 35,000 years ago
- Answer: C
- Who isolated manganese from its black ore pyrolusite in 1774?
- A) Johann Heinrich Pott
- B) Johan Gottlieb
- C) A glass technologist in Berlin
- D) A student in Vienna
- Answer: B
- In what form does manganese primarily exist in nature?
- A) Free element
- B) Oxides and hydrides
- C) Minerals
- D) Alloys
- Answer: C
- Which mineral is the major source of manganese?
- A) Bixbyite
- B) Manganite
- C) Rhodochrosite
- D) Pyrolusite
- Answer: D
- Which countries are major miners and suppliers of manganese to the world?
- A) Brazil, China, India
- B) Georgia, Russia, South Africa
- C) USA, Canada, Mexico
- D) Japan, Australia, Germany
- Answer: B
- Is manganese a magnet?
- A) Yes
- B) No
- Answer: B
- What is the melting point of manganese?
- A) 1046°C
- B) 1246°C
- C) 1446°C
- D) 1646°C
- Answer: B
- In biological systems, what role does manganese play?
- A) Energy production
- B) Bone strengthening
- C) Vitamin C absorption
- D) Protein synthesis
- Answer: B
- What is the main use of manganese in steel and iron production?
- A) Catalyst
- B) Alloy
- C) Fuel
- D) Lubricant
- Answer: B
- What is manganese dioxide used for in dry cell batteries?
- A) Conductor
- B) Electrolyte
- C) Filler
- D) Insulator
- Answer: C
- Why are manganese alloys used in soft drink cans?
- A) Lightweight
- B) Corrosive resistant
- C) Conductive
- D) Transparent
- Answer: B
- Which is the only stable isotope of manganese in nature?
- A) Manganese-50
- B) Manganese-55
- C) Manganese-60
- D) Manganese-65
- Answer: B
- How many known isotopes does manganese have?
- A) 15
- B) 21
- C) 27
- D) 33
- Answer: B
- What is the mass range of manganese isotopes?
- A) 30 to 50
- B) 40 to 60
- C) 46 to 66
- D) 56 to 76
- Answer: C
- What medical condition can long-term exposure to high manganese levels cause?
- A) Anemia
- B) Migraine
- C) Manganism
- D) Arthritis
- Answer: C
- How many electrons does manganese have in its pure form?
- A) 20
- B) 25
- C) 30
- D) 35
- Answer: B
Summary
In this tutorial on manganese, we delved into its various aspects, including its properties, historical significance, natural occurrence, biological roles, applications, and isotopes.
- Introduction:
- Manganese is a transition metal in Group VII b with atomic number 25 and atomic mass 54.
- Symbol: ‘Mn.’
- Naming and History:
- Possible origins of the name: Latin word “magnes” (magnet) or “magnesia nigra” (black magnesium oxide).
- Historical use dates back to prehistoric cave painters around 30,000 years ago.
- Occurrence of Manganese:
- Does not exist as a free element; found in oxides and hydrides.
- Major manganese-containing mineral: Pyrolusite, along with bixbyite, manganite, rhodochrosite, and rhodonite.
- Major suppliers: Georgia, Russia, South Africa, Ukraine, and Australia.
- Properties of Manganese:
- Hard, brittle pinkish, whitish-grey metal; not a magnet.
- Easily oxidized; oxidizes to manganese oxides on heating.
- Melting point: 1246°C, Boiling point: 2061°C, Density: 7.3 g/cm³.
- Manganese in Biological Systems:
- Essential bioelement acting as a cofactor for enzymes.
- Vital for plant enzymes converting water into oxygen.
- Deficiency addressed through fertilizers; used as a supplement for animals.
- Human role: Part of many enzymes, bone strength, and vitamin B1 absorption.
- High amounts are toxic and can lead to manganism with Parkinson’s-like symptoms.
- Uses of Manganese:
- Mainly used (around 90%) in making alloys for steel and iron production.
- Widely demanded in stainless steel production when mixed with aluminum.
- Manganese dioxide used as a filler in dry cell batteries.
- Manganese dioxide employed as a drying agent in black paints.
- Organo-manganese compounds used to reduce engine knocking and increase octane number.
- Corrosion-resistant aluminum alloys used in soft drink can production.
- Isotopes of Manganese:
- 21 known isotopes with mass ranges from 46 to 66.
- The only stable isotope in nature is Manganese-55.
This tutorial provides a comprehensive understanding of manganese, highlighting its diverse applications, biological importance, and the role it plays in various industrial processes.