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प्रश्न
Define: Molecule
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उत्तर
Molecule: A molecule can be defined as the smallest unit of an element or a compound which exhibits all the properties of that element or compound and has an independent existence. They are divisible into atoms.
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संबंधित प्रश्न
Name: the Hardest Naturally Occurring Substance
Name: Three different forms of carbon
Give reason: A frying pan is made up of steel but its handle is made up of wood.
Fill in the blank
_________ refers to the number of atoms in the molecule of an element
Indicate whether the following statement is true or false:
Noble gases are high reactive
Differentiate between the terms –
elements, compounds & mixtures.
The important physical properties of substances are colour, odour, nature, density & solubility in water.
Name – two coloured gases (with their colours)
Match the compounds in List I – 1 to 20 with their correct formulas from in List II-A to T.
| List I | List II | ||
| 1 | Hydrochloric acid | A | NaCI |
| 2 | Potassium Hydroxide | B | NaOH |
| 3 | Sulphuric Acid | C | KCI |
| 4 | Zinc Hydroxide | D | Ca(OH)2 |
| 5 | Sodium Chloride | E | CaS |
| 6 | Nitric Acid | F | CuSO4 |
| 7 | Calcium Hydroxide | G | CaCO3 |
| 8 | Carbonic Acid | H | NH4CI |
| 9 | Sodium hydroxide | I | HCI |
| 10 | Copper sulphate | J | ZnO |
| 11 | Potassium Chloride | K | HNO3 |
| 12 | Calcium Carbonate | L | H2CO3 |
| 13 | Magnesium Sulphide | M | MgS |
| 14 | Zinc Sulphate | N | MgO |
| 15 | aluminium Hydroxide | O | KOH |
| 16 | Sodium Carbonate | P | ZnSO4 |
| 17 | Calcium Sulphide | Q | Na2CO3 |
| 18 | Magnesium Oxide | R | H2SO4 |
| 19 | Zinc Oxide | S | AI(OH)3 |
| 20 | Ammonium Chloride | T | Zn(OH)2 |
‘The modern periodic table consists of elements arranged according to their increasing atomic numbers’. With reference to elements with atomic numbers 1 to 20 only in the periodic table – differentiate them into – metallic elements, metalloids, non-metals & noble gases.
Select the correct answer from A, B, C, D & E for the statement given below :
A noble gas.
