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प्रश्न
Select the correct answer from the choice in the bracket.
The least reactive metal.
पर्याय
magnesium
silver
copper
उत्तर
silver
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संबंधित प्रश्न
Write true or false
All pure substances have characteristic melting and boiling points.
Why is it necessary to separate the constituents of a mixture.
Name: a Non-metal Which is a Good Conductor of Electricity.
State the number of atoms of CaCO3
Name A substance used as an insulator.
Answer the following question:
When iron is mixed with sulphur at room temperature, it does not form a compound. Why?
Find the atomicity of the Following molecule:
Carbon Monoxide
The important physical properties of substances are colour, odour, nature, density & solubility in water.
Name – two coloured gases (with their colours)
Give the name of the radical - SO4
Complete the statement given below by filling in the blanks with the correct words.
Atom contains ________ , with positively charged _____.
Match the statements in List I – 1 to 10 correct answers in List II-A to J.
| List I | LIst II | ||
| 1 | Fluorine and chlorine | A | Nitrogen |
| 2 | A diatomic molecule | B | Boron |
| 3 | A molecule containing the elements hydrogen and oxygen. | C | Reactants |
| 4 | A metalloid - showing properties of both metals and non-metals. | D | Chemical Formula |
| 5 | The term used for the substances which take part in the chemical reaction | E | Halogens |
| 6 | The term represents a substance by means of symbols. | F | Water |
| 7 | The term used for the substances formed as a result of a chemical reaction | G | Nitric Acid |
| 8 | A compound containing one atom of zinc and two atoms of chlorine. | H | Products |
| 9 | The chemical name for nitrogen monoxide. | I | Phosphorus |
| 10 | A polyatomic molecule. | J | Zinc Chloride |
Represent with the help of a simple chart how matter is classified into pure or impure substances & further into elements, compounds & mixtures, with elements further segmented.
With reference to elements – define the term ‘molecule’. Give two examples each of a monoatomic, diatomic & polyatomic molecule.
Match the separation of components in List I with the most appropriate process in List II.
| List I | List II |
| 1. Naphthalene from naphthalene & sodium chloride. | A: Separating funnel |
| 2. Cream from milk. | B: Sublimation |
| 3. Kerosene oil from kerosene oil & water. | C: Boiling |
| 4. Lead nitrate from an aqueous solution of lead nitrate. | D: Centrifugation |
| 5. Ammonia from an aqueous solution of ammonia. | E: Distillation |
Non-metal conducting electricity :______ :: Metal conducting electricity : Copper
Match the following.
| Atom | Building block of matter |
| Element | Atoms of different kinds |
| Compound | Atoms of the same kind |
| Molecule | Smallest unit of a substance |
Give two example of elements.
Match the following:
| 1. | Co2 | a. | Robert Boyle |
| 2. | Sulfur | b. | Making mobile phones |
| 3. | Element | c. | triatomic molecule |
| 4. | Gallium | d. | Polyatomic molecule |
Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
Name a non-metal other than carbon that shows allotropy.
Higher-Order Thinking questions:
Why is hydrogen considered an element?
