7 Characteristics of Metalloids: Detailed Explanations


Only 7 elements are metalloids from the total elements of periodic table, characteristic of metalloids consisting of characteristic of both metals and non-metals.

There are so many elements are being used in our day-to-day life. There are total 118 elements in the periodic table. From these 118 elements there are 92 metals, 20 non-metals and only 7 elements are metalloids present in periodic table. So, metals are more in quantity in the periodic table and they are situated in the left side columns of the periodic table.

Non-metals situated on the right hand side of the periodic table. The elements showing characteristics of metalloids are situated in the midway section of the metals and non-metals in the periodic table.

Elements showing characteristics of metalloids listed are follows:

Metalloids are also known as semimetals. In the book Metals Metalloids (In the periodic table of the elements) by Monica Halka and Brian Nordstrom, they stated that the polonium (Po) is also classified as metalloid. Even though astatine (At) also sometimes recognised as metalloids and treated in the group of halogens.

The elements in the lower left side of the periodic table allied to the metallic properties for ex, cesium (Cs). As we go from the left to right in the periodic table the metallic properties becomes less and less in their characteristic. So the elements of the right side of the periodic table are non-metals in characteristics. The metalloids show the section of the periodic table in which the transition of elements can see from metals to non-metals. Metalloid mostly shows the physical characteristics like metals and chemical characteristics like non-metals.

Most vital physical characteristic of the metal is its capacity to conduct electricity. So, due to this characteristic of metalloids that is the capacity to conduct electricity, the semi-metals or metalloids are known as semiconductors to produce electricity. Metalloids can also show other properties of metals like malleability, ductility, conduction of heat and lustrous characteristic. Similarly, metalloids bear a resemblance to non-metals in chemical properties.

The metalloids descriptions are as follows:

1. Boron

Symbol: B

Atomic number: 5

Electronic configuration: 1s2, 2s2, 2p1

Boron is an element which is black in colour having metallic look or structure. The main source from which boron can form is mineral borax, then another source is colemanite and occasionally small amount of boron has formed from spring waters of volcanic eruption. Tourmaline found in igneous rocks has huge number of various elements contains 10% of boron by weight in it.

Borax term comes from Arabic or Persian word ‘borak’ means “white”. Boron resembles carbon atom in the formation of long chain molecule with covalent bond. Carbon hydrides and boron hydrides are analogous to each other. As the compounds of hydrocarbons are CH4, C2H6, C4H10, etc. And the compounds of boron hydrides are B2H6 (diborane), B4H10 (tetraborane), B5H9 (pentaboron), etc.

characteristics of metalloids
Boron Mineral

Uses:

  1. Borax and boric acid used as antiseptics having characteristics of antifungal and antibacterial material, its used for extermination of insects specially boric acid used to execute house borers, fleas and roaches.
  2. Boron is used as rocket fuels.
  3. Boron also used in fireworks and as water softeners
  4. Carboranes are used to develop novel polymers, reagents, anticancer drugs, ceremics and catalyst.
  5. Borons with other elements used in aerospace structures and fibre optics.

2. Silicon

Symbol: Si

Atomic number: 14

Electronic configuration: [Ne] 3s2, 3p2

After oxygen silicon’s abundance is second on earth. Silicon is a lustrous solid with dark grey in colour. The source of formation of silicon is sand and quartz minerals. Silicon can found anywhere, silica i.e. SiO2 (silicon dioxide) is present in quartz and quartz in crushed form gives sand. The silicon name is formed from the silica mineral. Silicon looks silvery lustrous so one can consider it as a metal, but it is a metalloid having the characteristics both of metals and non-metals.

Silicon metal

Uses:

  1. The most common use of silcon and germanium is as a semiconductor.
  2. Silicon dioxide is used to make quartz and ordinary glass.
  3. Iron and silicon (ferrosilicate) used in steel industry.
  4. Silicons are used in water proofing, talcum powder, water softeners, rubbers, ceramics and paints.

3. Germanium

Symbol: Ge

Atomic number: 32

Electronic configuration: [Ar] 4s2, 3d10, 4p2

Germanium is brittle and hard metal like element. It is grayish white in colour. Basically the source of formation of germanium is the sulphide ores associated with other elements like tin, zinc, silver, lead and antimony.

Germanium crystals

Uses:

  1. Germanium used to make transistors.
  2. Germanium is used to strengthen other alloys like aluminium, magnesium and tin.

4. Arsenic

Symbol: As

Atomic number: 33

Electronic configuration: [Ar]4s23d104p3

Arsenic comes under very toxic elements, having seventeen radioactive isotopes and single stable isotope with two allotropes i.e. a brittle grey solid and a yellow solid. ‘Arsenic’ word comes from Greek word ‘yellow orpiment’. Orpiment was a common mineral consist of arsenic sulphide. Arsenic is not form in pure form, it is always formed in mineral or sulphide forms.  Arsenic exists as an arsenic sulphide (As2S3) in yellow mineral orpiment.

Arsenic metal

Uses:

  1. Arsenic used as indium arsenide, arsenic and arsenide ion gallium in semiconductor industry.
  2. In manufacture of weed killers and insecticides white arsenic is used.
  3. In some rodenticides and ant pastes arsenic used as poison.
  4. Mixed elements compounds like copper, arsenic and chromium used as wood preservative.

5. Antimony

Symbol: Sb

Atomic number: 51

Electronic configuration: [Kr]5s24d105p3

Antimony has thirty one radioactive isotopes and two stable isotopes. Stibnite is the most common mineral containing antimony. Also antimony is mostly found in copper, lead, silver and arsenic deposits. Idaho, China and Bolivia are the places where antimony found from mines worldwide. Antimony means ‘not by yourself’. That means antimony is also not found in pure form it is always found in minerals. Stibnite crystals are the most general mineral which containing antimony. Antimony exists as antimony sulphide (Sb2S3) in black mineral stibnite. Arsenic consumption is more than antimony consumption due to more use of arsenic in semiconductor industry.

Stibnite or antimony mineral

Uses:

  1. Some antimony and arsenic compounds are still used to kill various harmful microorganisms and this usage should be harmful for patients.
  2. The main use of antimony is a fabric and plastics flame retardant.
  3. In lead storage batteries antimony is used.
  4. Various catalytic substances, paints and glasses are composed of antimony compounds.

6. Tellurium

Symbol: Te

Atomic number: 52

Electronic configuration: [Kr]4d105s25p4

Tellurium is a brown solid element with soft texture. It is a huge number of stable isotopes which are naturally occurring and have various industrial applications. Tellurium and polonium both are most rare elements in space and on earth. Telluride occurs in a selenide mineral and as few sulphide on earth. Tellurium is generally formed as a by-product of mining.

Tellurium (Te) element

Uses:

  1. Tellurium has used in various industries even if it is rare element.
  2. In steel industry tellurium is used to increase corrosion resistance and to increase ductility.
  3. Tellurium is used for cracking of petroleum.
  4. In electroplating baths tellurium used as brightener.
  5. Compounds of tellurium are used as colouring agents in glass.

7)   Polonium

Symbol: Po

Atomic number: 84

Electronic configuration: [Xe]6s24f145d106p4

Polonium is formed from radioactive decay of various elements and not found on earth naturally. As isotopes of polonium has short half-life and occurs in the rocks which containing radium, uranium and thorium. Polonium is more metallic in nature than tellurium and can form salts with metals.

Uses:

  1. Polonium works as the high-activity alpha emitter that inductees the alpha-beryllium reaction to create neutrons which then excite uranium fission.
  2. Polonium is also now notorious as an effective harmful material.
  3. In future, polonium 210 should be used to clout long-distance space flight.

Dr. Shruti Ramteke

Hello everyone I am Dr. Shruti M Ramteke, i did my Ph.D in chemistry. I have five years of teaching experience for 11-12 standard, B,Sc and MSc in chemistry subject. I have published total five research articles during Ph.D on my research work and i have fellowship from UGC for my Ph.D. My Masters with specilization Inorganic chemistry and my graduation with chemistry, zoology and environmental science subjects. thank You

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