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प्रश्न
What are elements? What are they made of?
उत्तर
- Elements are chemically the simplest substances and hence cannot be broken down using chemical reactions.
- It is made of entirely from one type of atom.
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संबंधित प्रश्न
Correct the following statement:
CO and Co both represents cobalt.
Give two examples of the following.
Non-metals which are solids
Answer the following question:
Give the advantages of using symbols instead of names of elements or compounds.
Tick (√) the correct alternative from the choice given for the following statement.
All pure substances have
Differentiate between the terms –
elements, compounds & mixtures.
Give the name of the radical - NO3
Complete the statement with the correct words.
_______ are chemicals which are hydroxide (or oxides) of ______ eg. sodium hydroxide.
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 |
Assertion: Air is a mixture of elements only.
Reason: Only nitrogen, oxygen and neon gases exist in air.
Higher-Order Thinking questions:
Why is hydrogen considered an element?
