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प्रश्न
Fill in the blank
A metal that gives dazzling effect to crackers when they explode is ______
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उत्तर
A metal that gives dazzling effect to crackers when they explode is magnesium.
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संबंधित प्रश्न
Give a reason for the following:
Alkali metals are good reducing agents.
The atomic number of an element Y is 16.
- What must an atom of Y do to achieve the nearest inert gas electron arrangement?
- Which inert gas is nearest to Y?
Name an alloy of lead and tin.
Which property of ‘solder’ alloy makes it suitable for welding electrical wires?
Explain how, a reduction reaction of aluminium can be used for welding cracked machine parts of iron. Write a chemical equation for the reaction involved.
What is an alloy?
Write ‘True’ or ‘False’ in front of following statement.
Brass is an alloy of copper and zinc and has lustrous yellow colour.
State two important uses of following metals:
Uses of iron
Take an element from an alkali metal and one from an alkaline earth metal and write an equation for their action with:
Hydrochloric acid,
Take an element from an alkali metal and one from an alkaline earth metal and write an equation for their action with:
Sulphuric acid
Write name.
The device used for grinding an ore.
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
An amorphous substance which turns from pale green to black on strong heating evolving a colourless, acidic gas as the only gaseous product.
When a copper coin is dipped in the solution of silver nitrate, it shows a lustre on its surface. Explain this process with the help of a chemical equation.
Higher Order Thinking Skills.
Aakash noticed that the metal latch on gate was difficult to open during hot sunny days. However, it was not difficult to open the same latch at night. Aakash observed that the latch and the gate are exposed to the sun during day time.
- Formulate a hypothesis based on the information provided.
- Briefly state how you would test the hypothesis.
Which of the following two combinations are correct?
| Metal | Gas Evolved | |
| (i) | Copper | Yes |
| (ii) | Iron | Yes |
| (iii) | Magnesium | No |
| (iv) | Zinc | Yes |
Name one metal and one non-metal that exist in liquid state at room temperature. Also name two metals having melting point less than 310 K (37°C)
______ is the first scientist who used the term element.
Silver and copper are very good conductors of electricity.
Why are metalloids called semimetals?
X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information, complete the following:
Metal atoms tend to have a maximum of ______ electrons in the outermost shell.
