Non-metals അലോഹങ്ങൾ
The chapter opens with the periodic table. Five boxes stand out from it: hydrogen, carbon, nitrogen, oxygen and chlorine. These are five important non-metals, and you will meet each one in turn. You will make hydrogen from zinc and acid and hear (virtually) its “pop”. You will see why it is a fuel with the highest calorific value, and also why it is hard to use. Carbon comes in many forms called allotropes: hard diamond, slippery graphite, one-atom-thick graphene and the football-shaped fullerene. Carbon dioxide turns lime water milky and puts out fires, while carbon monoxide is a silent poison. Nitrogen is the lazy gas of the air, held together by a strong triple bond, yet lightning and tiny root bacteria turn it into plant food. Oxygen keeps us alive, and its cousin ozone shields the Earth from ultraviolet rays. Chlorine bleaches cloth and makes drinking water safe. This self-study guide starts from the basics and explains every idea with animations and virtual labs. It answers every textbook question and ends with a revision sheet and a model test.
The chapter in one picture
Part 1: the five non-metals of this chapter (അലോഹങ്ങൾ) and their places in the periodic table (page 1). Part 2: diamond (വജ്രം), graphite (ഗ്രാഫൈറ്റ്) and fullerene (ഫുള്ളറീൻ) are all pure carbon. Different forms of the same element are allotropes (രൂപാന്തരങ്ങൾ, page 5). Part 3: the great heat of lightning makes nitrogen and oxygen combine, N₂ + O₂ → 2NO, the first step from air to the nitrates in the soil (page 7). Atoms are drawn far bigger than they really are.
The chapter at a glance
🎈 Hydrogen and 💎 carbon
- Hydrogen: the most abundant element in the universe · Zn + 2HCl → ZnCl₂ + H₂↑ · burns with a “pop” (പോപ്പ് ശബ്ദം)
- Hydrogen as a fuel (ഇന്ധനം): highest calorific value (കലോറിക മൂല്യം), 143 kJ/g, and only water is formed
- Allotropes of carbon: crystalline (diamond, graphite, graphene, fullerene) and amorphous (charcoal, coke, lamp black, coal)
- Carbon dioxide: CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂ · turns lime water (ചുണ്ണാമ്പുവെള്ളം) milky
- Carbon monoxide is poisonous · carbonates (കാർബണേറ്റുകൾ): the barium chloride test
🌩️ Nitrogen, 🫁 oxygen and 🧴 chlorine
- Nitrogen: 78 % of air, inert (നിഷ്ക്രിയം) because of the N≡N triple bond · lightning · nitrogen fixation (നൈട്രജൻ സ്ഥിരീകരണം) · fertilisers
- Oxygen: 2KMnO₄ → K₂MnO₄ + MnO₂ + O₂ · a glowing splinter bursts into flame · supporter of combustion (ജ്വലനസഹായി)
- Ozone (O₃) absorbs ultraviolet radiations (അൾട്രാവയലറ്റ് വികിരണങ്ങൾ) · CFCs cause ozone layer depletion (ഓസോൺ പാളിയുടെ ശോഷണം)
- Chlorine: greenish-yellow and pungent · bleaches only when moist, by nascent oxygen (നവജാത ഓക്സിജൻ)
- Bleaching powder (ബ്ലീച്ചിങ് പൗഡർ) · the chloride test with silver nitrate
How to use this guide
🎬 Watch the animations
Hydrogen bubbles off zinc, carbon atoms turn in 3-D as diamond, graphite and a buckyball, lightning builds nitric oxide and ozone soaks up ultraviolet light. Press Next ▶ or ▶▶ Auto play in the step-by-step boxes. Animations pause by themselves when you scroll away; click a lab to start its clock again.
🧪 Use the virtual labs
A metal / non-metal / metalloid sorter, a gas-test bench (pop test, glowing splinter, lime water), a fuel chart, an allotrope explorer, a carbonate test, a lightning-to-nitrate chain, an ozone cycle and a bleaching lab. Dangerous experiments with chlorine or hot permanganate are shown only as safe virtual teacher demonstrations.
✍️ Try before you see
Every textbook table is a fill-in table with a check button, and every question hides its answer behind a button. Work it out in your notebook first. The “Check yourself” quizzes at the end of each page tell you at once whether you are right.
📖 Textbook words
Purple മലയാളം words are the exact terms used in your textbook (pages 133–152), so you can match this guide with your book and write answers in either language.
🔇 Quiet and offline
The pages make no sound and need no internet. Optional “Explore online” boxes link to checked websites (no videos); they open only if you click them. Every page is a single file, so the whole guide works on a computer or phone with no connection.
Learning path
Follow the pages in order. If you already know metals and non-metals, electron configurations, covalent bonds, the common gas tests and how to balance an equation, you can skim pages 1–2. Still try their quizzes, because the chapter uses these ideas on every page.
Two scientists you will meet
Henry Cavendish
1731–1810 · British scientist- Discovered hydrogen in 1766.
- He called it inflammable air (കത്തുന്ന വായു) because it catches fire so easily.
- The name hydrogen comes from the Greek word Hydrogenes, “water-producer”: burning hydrogen gives water.
- Read his side box on page 3 (textbook page 134).
Joseph Priestley
1733–1804 · English scientist- Discovered oxygen in 1774.
- The French scientist Lavoisier gave it its name, from the Greek word oxygenes, “acid-producer”.
- Oxygen is called പ്രാണവായു, the “life gas”.
- Read his side box on page 8 (textbook page 146).
Safety first
- Hydrogen burns explosively when mixed with air. Keep flames away from any hydrogen generator; only the small test-tube “pop” test is done, with the teacher.
- Chlorine is poisonous. Its preparation from potassium permanganate and concentrated hydrochloric acid (Fig 7.10) is a teacher demonstration in a fume cupboard; in this guide it is only virtual.
- Carbon monoxide has no colour and no smell but is poisonous. Never burn charcoal or a stove in a closed room, and never run an engine in a closed garage.
- Heating potassium permanganate (Fig 7.9), handling concentrated acids and dry ice (it causes frostbite) are for the teacher only.
- Never smell a gas straight from a jar and never taste any laboratory chemical. Wear safety glasses when your teacher asks.
Quick glossary (Malayalam ↔ English)
| Textbook term | English | Meaning |
|---|---|---|
| അലോഹങ്ങൾ · ലോഹങ്ങൾ · ഉപലോഹങ്ങൾ | Non-metals · metals · metalloids | Elements that are usually dull, brittle and do not conduct · shiny, malleable conductors · elements with some properties of each (boron, silicon …) |
| മൂലക കുടുംബങ്ങൾ | Element families | Groups of the periodic table with similar elements: the halogens, the carbon family … |
| സ്വതന്ത്രാവസ്ഥ · സംയുക്താവസ്ഥ | Free state · combined state | The element on its own (N₂ in air) · joined with other elements in a compound (hydrogen in water) |
| ഐസോടോപ്പുകൾ | Isotopes | Atoms of one element with different numbers of neutrons: protium, deuterium and tritium are isotopes of hydrogen |
| കത്തുന്ന വായു | Inflammable air | Cavendish's name for hydrogen |
| ജലത്തിന്റെ വൈദ്യുതവിശ്ലേഷണം | Electrolysis of water | Splitting water into hydrogen and oxygen with electricity: 2H₂O → 2H₂ + O₂ |
| ദ്വയാറ്റോമിക തന്മാത്ര | Diatomic molecule | A molecule of two atoms: H₂, N₂, O₂, Cl₂ |
| പോപ്പ് ശബ്ദം | “Pop” sound | The small explosion when a burning splinter is brought to hydrogen: the test for hydrogen |
| പൂരിത എണ്ണകൾ | Saturated oils | Solid fats such as vanaspati, made by adding hydrogen to vegetable oils |
| നിരോക്സീകാരി | Reducing agent | A substance that removes oxygen from a compound: hydrogen and carbon monoxide take oxygen away from metal oxides |
| ഇന്ധനം · കലോറിക മൂല്യം | Fuel · calorific value | A substance burnt for heat · the heat energy released when unit mass of a fuel burns completely (kJ/g) |
| രൂപാന്തരങ്ങൾ · രൂപാന്തരത്വം | Allotropes · allotropy | Different forms of the same element with different physical properties · the existence of such forms |
| ക്രിസ്റ്റലീയ · അമോർഫസ് | Crystalline · amorphous | With atoms in a regular pattern (diamond) · without a regular pattern (charcoal) |
| വജ്രം · ഗ്രാഫൈറ്റ് · ഗ്രഫീൻ · ഫുള്ളറീൻ | Diamond · graphite · graphene · fullerene | The crystalline allotropes of carbon |
| ചാർക്കോൾ · കോക്ക് · വിളക്കുകരി · കൽക്കരി | Charcoal · coke · lamp black · coal | The amorphous forms of carbon |
| അപവർത്തനാങ്കം | Refractive index | How strongly a substance bends light; diamond's is high, so it sparkles |
| താപചാലകത · വൈദ്യുതചാലകത | Thermal conductivity · electrical conductivity | How well a substance carries heat · electricity |
| സ്നേഹകം | Lubricant | A substance that makes surfaces slide easily: graphite |
| ബക്കിബോൾസ് · ബക്കിട്യൂബ്സ് | Buckyballs · buckytubes | Fullerenes shaped like hollow balls (C₆₀) · like hollow tubes (carbon nanotubes) |
| നാനോടെക്നോളജി | Nanotechnology | Technology with materials a few nanometres in size, such as graphene and nanotubes |
| തിസിൽ ഫണൽ | Thistle funnel | A long funnel with a round bulb at the top, used to add acid into a flask (Fig 7.8) |
| ചുണ്ണാമ്പുവെള്ളം | Lime water | A clear solution of calcium hydroxide, Ca(OH)₂; carbon dioxide turns it milky |
| അഗ്നിശമനികൾ | Fire extinguishers | Devices that put out fires; many use carbon dioxide |
| അലക്കുകാരം · അപ്പക്കാരം | Washing soda · baking soda | Na₂CO₃·10H₂O · NaHCO₃ (used for appam) |
| കാർബൊജൻ | Carbogen | 95 % oxygen + 5 % carbon dioxide, used for artificial respiration |
| ഡ്രൈ ഐസ് | Dry ice | Solid carbon dioxide, used for stage “smoke” |
| കാർബോക്സീഹീമോഗ്ലോബിൻ | Carboxyhaemoglobin | Formed when carbon monoxide joins haemoglobin, so the blood carries less oxygen |
| വാട്ടർ ഗ്യാസ് · പ്രൊഡ്യൂസർ ഗ്യാസ് | Water gas · producer gas | CO + H₂ · CO + N₂ (industrial fuels) |
| കാർബണേറ്റുകൾ · ബൈകാർബണേറ്റുകൾ · കാർബോണിക് ആസിഡ് | Carbonates · bicarbonates · carbonic acid | Salts of carbonic acid, H₂CO₃: marble (CaCO₃), washing soda, baking soda |
| നിഷ്ക്രിയം | Inert | Does not react easily; nitrogen at ordinary conditions |
| നൈട്രജൻ സ്ഥിരീകരണം | Nitrogen fixation | Turning nitrogen of the air into compounds plants can use (by lightning, or by Rhizobium bacteria in root nodules) |
| ജൈവവളം · രാസവളം | Organic manure · chemical fertiliser | Manure from plant and animal waste · factory-made fertiliser such as urea |
| ശീതീകാരി | Refrigerant (coolant) | A substance used for cooling: liquid nitrogen |
| പ്രാണവായു | Oxygen (“life gas”) | The gas we need to breathe |
| ജ്വലനസഹായി | Supporter of combustion | Helps other things burn but does not burn itself: oxygen |
| ഓസോൺ പാളിയുടെ ശോഷണം | Ozone layer depletion | Thinning of the ozone layer, mainly by chlorine from CFCs |
| അൾട്രാവയലറ്റ് വികിരണങ്ങൾ | Ultraviolet radiations | Invisible, harmful rays from the Sun; ozone absorbs them |
| ഗ്രീൻ ഹൗസ് വാതകം | Greenhouse gas | A gas that traps heat in the atmosphere; ozone is one |
| ക്ലോറോഫ്ലൂറോകാർബണുകൾ (CFC) | Chlorofluorocarbons | Compounds of chlorine, fluorine and carbon once used in refrigerators and ACs |
| ബ്ലീച്ചിങ് പൗഡർ | Bleaching powder | Ca(OCl)₂, made from dry chlorine and dry slaked lime; used to disinfect water |
| നവജാത ഓക്സിജൻ · ഹൈപ്പോക്ലോറസ് ആസിഡ് | Nascent oxygen · hypochlorous acid | [O], newly formed and very reactive; it bleaches · HOCl, formed from chlorine and water |
| അണുനാശിനി · കീടനാശിനി | Disinfectant · pesticide | Kills germs · kills pests |
🌐 Explore online (optional)
Want to go further? The teaching pages end with a few checked websites (no videos), and page 12 has the full resources hub. They need the internet; the guide itself works offline. To begin, read about non-metals in general, try building molecules in a simulation, or look at the many forms of carbon:
- 📄 Nonmetal Wikipedia
All about the non-metal elements. - 🧪 Build a Molecule (PhET simulation) PhET, University of Colorado Boulder
Build H₂, O₂, N₂, CO₂, H₂O and more. - 📄 Allotropes of carbon Wikipedia
Diamond, graphite, graphene, fullerenes and amorphous carbon. - 📄 Diamond Wikipedia
The hardest natural substance – each carbon bonded to four others. - 📄 Graphite Wikipedia
Layers that slide, free electrons that conduct. - 📄 Graphene Wikipedia
A single layer of graphite – light, strong and conducting. - 📄 Fullerene Wikipedia
Buckyballs and buckytubes (carbon nanotubes). - 📄 Carbon nanotube Wikipedia
Cylinder-shaped fullerenes used in nanotechnology.
Made for self-learning. Works offline – every page is a single file; only the optional "Explore online" links need the internet. Study material prepared by Claude for Madhu's family study folder, October 2026.