Non Metals in Daily Life

Non Metals in Daily Life

Non-Metals

In the modern periodic table there are 24 nonmetals; 11 are gases, 1 is liquid (Br₂), and 82 are solid. Electronegative elements are nonmetals. Non-metals are bad conductors of heat and electricity except for graphite, Si & Ge, which are semiconductors.

Hydrogen (H₂)

Hydrogen is the lightest ggas,having three isotopes:

¹H¹, ¹H², ¹H³.

• Protium, Deuterium, Tritium (Radioactive).

• Protium is the only isotope in the periodic table having zero neutrons.

• Deuterium oxide is known as heavy water and used in nuclear reactors as a moderator.

• Liquid hydrogen is used as rocket fuel.

• Hydrogen is known as a range element because it may be kept in Group I & Group VII A.

Water (H₂O)

Water is a polar molecule.

Hard and Soft Water

• Hard water – less froth with soap.

• Soft water – More froth with soap.

Hard water – due to the presence of soluble impurities of bicarbonates, chlorides & sulphates of Ca & Mg.

• Temporary hardness – due to the presence of bicarbonate of calcium and magnesium.

• Permanent hardness – due to the presence of chlorides and sulphates of calcium and magnesium.

Temporary hardness is removed by boiling and by Clark's method, while permanent hardness is removed by the soda ash (Na₂CO₃) process.
Permanent hardness is also removed by the permutit process.

Structure of Ice

• In ice, every molecule of H₂O is associated with four molecules by hydrogen bonding in a tetrahedral fashion.

• Thus, ice has an open structure with large empty space due to the existence of hydrogen bonding.

• Thus, ice has less density than water.

• As ice melts at 0°C, a number of hydrogen bonds are broken and space between water molecules decreases, so the molecules move closer together.

• Therefore, the density of water increases and is maximum between 0°C and 4°C.

• Above 4°C, the kinetic energy increases, causing molecules to disperse, so density decreases with an increase in temperature.

Hydrogen Peroxide (H₂O₂)

Hydrogen Peroxide – blue colour, density = 1.44 g/cm³, more than that of water (1 g/cm³).

• Used as a bleaching agent for fine and delicate materials.

• Also used as hair bleach.

• Acts as an antiseptic for washing wounds, ears, teeth, etc., under the name of Perhydrol.

• Also used as rocket fuel.

Heavy Water (D₂O)

Heavy water (D₂O) is injurious to plants, animals, and humans.

• Ordinary water is the major source of life.

• This is probably due to the slower rate at which D⁺ ions participate in enzyme-catalysed reactions compared with H⁺ ions of ordinary water.

• Heavy water is used in nuclear reactors to slow down the speed of neutrons and is called a moderator.

Oxygen (O₂)

An important constituent of air, it exists in three isotopes: ¹⁶O, ¹⁷O, and ¹⁸O. Oxygen is a colourless, odourless and tasteless gas.

• The most abundant isotope is ⁸¹⁶O.

• In the atmosphere, O₂ ≈ 21% by volume.

Oxygen gas is released mainly as a result of photosynthesis in plants.

Photosynthesis reaction:

• 6CO₂(g) + 12H₂O(l) — Sunlight → C₆H₁₂O₆(aq) + 6O₂(g) + 6H₂O(l)

Oxygen uses:

• Used in artificial respiration, surgery, heart ailments, by mountaineers, and sea divers.

• Essential for respiration – forms oxyhaemoglobin in blood.

• Liquid oxygen is used as an oxidiser in space rockets.

• Also used in oxy-acetylene and oxygen-ethylene flames for welding and cutting.

Ozone (O₃)

Ozone is a pale blue gas with a pungent smell. Vapour density (V.D.) = 24, heavier than air (V.D. = 14). Ozone is neutral and does not change litmus colour.

Allotrope of Oxygen

• Ozone (O₃) is the allotrope of oxygen.

• Formed by the effect of ultraviolet rays in the atmosphere.

Uses of Ozone:

• Sterilizing water (germicide)

• Bleaching delicate fibres, oils, starch, ivory, etc.

• Used as disinfectant and in industry

• Used as bleaching agent in manufacture of silk and synthetic camphor

Carbon Monoxide (CO)

Highly poisonous/toxic gas. Combines with haemoglobin to form carboxyhaemoglobin, a stable complex (≈300 times more stable than oxyhaemoglobin). Prevents oxygen transport → causes suffocation and death.

Uses:

• A constituent of fuel gases such as water gas and producer gas (CO + N₂).

• Used in metallurgical reduction processes (CO + H₂).

Carbon Dioxide (CO₂)

Colourless, odourless, and 1.5 times heavier than air. Unlike CO, it is non-poisonous but causes asphyxiation by oxygen depletion.

• Liquefaction: Under 50–60 atm pressure at room temperature. On evaporation, it solidifies into dry ice (Drikold). Dry ice is used as a refrigerant.

• Carbogen mixture (5% CO₂ + 95% O₂) – used for artificial respiration in CO poisoning victims.

Nitrogen (N₂)

Forms 78% of the atmosphere by volume. Liquid nitrogen is used for refrigeration. Essential for protein synthesis.

Haber’s Process

• N₂ + 3H₂ —(Fe + Mo)/f→ 2NH₃

• Produces ammonia (NH₃).

Ammonia (NH₃)

Uses:

• As refrigerant

• In manufacture of HNO₃

• In fertilizers like urea, ammonium sulphate, etc.

• In manufacture of Na₂CO₃ and NaHCO₃

• In preparation of ammonium salts

• In preparation of explosives

• In preparation of artificial silk

• Nitrogen fixation in leguminous plants

Phosphorus (P)

Important constituent of animals and plants. Present in bones & DNA. Essential component of nucleic acids.

Allotropes

• White or yellow phosphorous

• Red phosphorous

• Black phosphorous

White phosphorus is more reactive than red phosphorus.

Sulphur Dioxide (SO₂)

Acts as a bleaching agent due to its reducing nature; bleaches in the presence of moisture.

Reaction:

• SO₂ + 2H₂O → H₂SO₄ + 2(H)

• Coloured matter + H → Colourless matter (Bleached)

• Bleaching by SO₂ is temporary.

On exposure to air, colour returns.

Halogens (Group 17 Elements)

Uses of Halogens

• In the preparation of UF₆ and SF₆ for energy production and dielectric constant.

• HF is used to synthesise chlorofluorocarbons (CFCs) and polytetrafluoroethylene (PTFE).

• Chlorofluorocarbon (Freon) – used as a refrigerant and aerosol.

• Non-stick utensils – made of Teflon.

• Chlorine – used to prepare PVC, insecticides, herbicides, etc.

• Chlorine bleaching action (oxidation):

Cl₂ + H₂O → 2HCl + (O)

Coloured substance + (O) → Colourless product (Bleached)

• Bleaching by chlorine is permanent.

• The colour cannot be restored.

• Used for vegetable and organic matter.

• Bromine – used in ethylene bromide synthesis, in leaded petrol, and in AgBr for photography.

Inert Gases (Noble Gases)

Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn) belong to Group 18. Except Rn, all are present in the atmosphere.

Uses:

• Argon – used in arc welding & electric bulbs.

• Helium – light & non-inflammable, used in balloons and weather indicators.

• Neon – used in discharge tubes to produce glow light.

Final Thoughts

Non-metals are essential elements found in various forms such as gases, liquids, and solids. They are generally poor conductors of heat and electricity, except for graphite, silicon, and germanium.

Hydrogen, the lightest element, forms water, heavy water, and hydrogen peroxide, each with distinct roles in daily life and industry. Oxygen and its allotrope ozone are vital for respiration and environmental balance. Elements like nitrogen, phosphorus, and sulphur are important for life processes and industrial applications.

Halogens such as chlorine and bromine serve as strong bleaching and disinfecting agents, while noble gases like helium and neon find use in lighting, balloons, and welding.