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Important Notes on Non-Metals and Metalloids

By BYJU'S Exam Prep

Updated on: September 25th, 2023

In this article, we will discuss the Non-Metals and Metalloids. One-liner type question usually comes from this topic.

Non-Metals:

  • Non-metal may be solid, liquid or gas.
  • Bromine is the only liquid non-metal.
  • Non-metals are the elements that do not have the properties of the metals.
  • They are the soft, non-lustrous, brittle, non-sonorous and poor conductor of heat and electricity .e.g. carbon, hydrogen, helium, neon krypton, etc.

In this article, we will discuss the Non-Metals and Metalloids. One-liner type question usually comes from this topic.

Non-Metals:

  • Non-metal may be solid, liquid or gas.
  • Bromine is the only liquid non-metal.
  • Non-metals are the elements that do not have the properties of the metals.
  • They are the soft, non-lustrous, brittle, non-sonorous and poor conductor of heat and electricity .e.g. carbon, hydrogen, helium, neon krypton, etc.

Important Non-metals

Carbon:

  • Carbon belongs to group 14 of the periodic table.
  • Carbon occurs both in a free state as well as in the combined state.
  • Carbon has two crystalline allotropes diamond and graphite.

Allotropes of Carbon:

Diamond:

  • Diamond is the hardest substance and is the bad conductor of electricity.
  • Diamond is the purest form of the Carbon
  • Used in the making of jewellery and cutting glass.

Graphite:

  • Graphite is an exception. It is a good conductor of heat and electricity.
  • Used in the nuclear reactor as a moderator.

Compounds of Carbon:

Carbon monoxide:

  • It is colourless, odourless, neutral and highly poisonous gas in nature.
  • Combines with hemoglobin to form Carboxyhaemoglobin, which is not able to absorb oxygen, as a result, leads to suffocation
  • Woodfire or coal fire in a closed room leads to the formation of the carbon monoxide which leads to the death of the persons in the rooms.

Carbon Dioxide:

  • Occur in the air to the extent of 0.03-0.05 percent.
  • Solid CO2 is known as dry ice.
  • Dry ice is used in the transport of perishable food material as it provides the cold and inert atmosphere which helps in killing bacteria, fungi, modules, etc.
  • Carbon dioxide is used by the plants in the process of photosynthesis for the formation of oxygen.
  • Carbides are the compound of carbon with metals or electro-negative elements.

Silicon(Si)

  • Silicon occurs in nature in the form of sand but never found in the free state.
  • This element which also exhibits the characteristic of allotropy.
  • This is the second most abundant element in the earth crust after oxygen
  • Used as a superconductor in making computer chips.
  • Silicon carbide is an artificial diamond called carborendum.
  • Silica is also called sand which exists most abundantly in the solid state in nature and used in the production of glass, cement, etc.
  • Quartz is a crystalline form of SiO2.

Nitrogen(N2) :

  • An important constituent of air about 79% by volume.
  • Used in the manufacturing of nitric acid, ammonia, and other nitrogen compounds.
  • As a refrigerant in liquid form.
  • To provide an inert atmosphere in different metallurgical operation.
  • Used as a preservative in the food packing.

Compounds of Nitrogen:

Ammonia:

  • The most important compound of nitrogen.
  • Prepared by Haber’s process.
  • It is soluble in water and its aqueous solution is alkaline in nature.
  • Used in refrigerator and manufacturing of fertilizers and explosives.
  1. Nitrous oxide (N2O) is used as laughing gas.
  2. The symbiotic bacteria present in the root nodules of leguminous plant convert the atmospheric nitrogen into compounds of nitrogen .e.g. Azobactor.

Phosphorus(P):

  • It is a highly reactive non-metal that is why it does not occur in the free state.
  • Phosphorus is an essential constituent of bones, teeth, blood nerves and tissue.
  • Bones contain 80% phosphorus.

Allotropes of phosphorus:

  • White phosphorus:
  • Red phosphorus
  • Black phosphorus
  • Scarlet phosphorus
  • Violet phosphorus

Oxygen

  • Oxygen exists in two allotropic forms that are in the most stable diatomic form(O2) and in a less stable triatomic form (O3) ozone.
  • Oxygen is the supporter of combustion but it is non-inflammable.
  • Oxygen dissolved in blood in the form of oxyhemoglobin.
  • Liquid oxygen mixed with freshly divided carbon is used in place of dynamite in coal mining.
  • Ozone is formed by the action of UV rays from the Sun on Oxygen and protects the living beings by not allowing UV rays to reach the earth.
  • Ozone is also used as germicide and disinfectant for sterilizing water and for detecting the position of the double bond in unsaturated organic compounds.

Sulphur(S):

  • Sulphur occurs in the free state in volcanic areas.
  • Sulphur exists in five allotropic forms.
  • Sulphur is used in the rubber industry for vulcanization of rubber.
  • Sulphuric acid is also known as oil of vitriol or king of chemicals.
  • Sulphuric acid is prepared by two processes i.e. lead chamber process and contact process.

Halogens:

  • Halogens are highly reactive elements and therefore they do not exist in the free state but exist only in combined form.
  • Halogens have the highest electron affinity so they act as strong oxidising agent.
  • Their oxidising power decreases from fluorine to iodine.

Chlorine(Cl2):

  • Chlorine is always present in the combined state in nature in the form of chlorides.
  • Chlorine was first discovered by Scheele by the action of hydrogen chloride on manganese dioxide.
  • Chlorine is used as a bleaching agent.
  • Reacts with water to form HCl and HCIO.
  • Used as a disinfectant and oxidizing agent.

Iodine:

  • It is used as an antiseptic as tincture of Iodine.
  • Used in the cure of Goitre.
  • Turns starch solution blue.

Noble Gases:

  • Helium, neon, argon, krypton, xenon, and radon are known as inert gases or noble gases.
  • These elements have completely filled valence shell and so these do not form chemical bonds.
  • These are always found in the free state but radon is not present in nature.
  • In the atmosphere, argon is the most abundant noble gas but in the universe, helium is the most abundant gas.
  • The mixture of Helium and Oxygen is used for artificial breathing of Asthma patients and by sea drivers.
  • Helium is used as a pressuring agent in rockets to expel liquid oxygen and liquid hydrogen.
  • Neon is used in a neon discharge lamp and signs for advertising purposes.
  • Xenon is also known as stranger gas and a combined mixture of xenon and krypton is used in high-intensity photographic flash tubes.
  • Radon is used in the preparation of an ointment for the treatment of cancer.
  • A mixture of argon and nitrogen is used in an electric bulb.
  • Krypton is used in high-efficiency miner’s cap lamps.

Metalloids:

  • They have properties of both metals and non-metals.
  • Six commonly known metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium.
  • Typical metalloids have a metallic appearance but they are the brittle and only fair conductor of electricity.
  • Metalloids and their  compounds are used in the manufacturing of alloys, biological agents, flames retarders, glasses, optical storage
 

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