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प्रश्न
The three important metalloids are.............................. and ..........................
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उत्तर
The three important metalloids are boron, silicon, and germanium.
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संबंधित प्रश्न
Define the term matter. What is it composed of?
Write true or false for each statement. Rewrite the false statement correctly.
Matter cannot exist in different states.
Which of the following materials fall in the category of a “pure substance”?
- Ice
- Milk
- Iron
- Hydrochloric Acid
- Calcium oxide
- Mercury
- Brick
- Wood
- Air
Describe in your own words, what happens to the particles when salt dissolves in water.
Explain why air is used to inflate tyres.
Bromine and air take about 15 minutes to diffuse completely but bromine diffuses into a vacuum very rapidly. Why is this so?
Name a non-metal which is a good conductor of electricity.
Name the property which enables metals to be drawn into wires.
What is meant by saying that metals are lustrous ?
Name a non-metal :
- which is lustrous
- which is required for combustion
- whose one of the allotrophic forms is a good conductor of electricity. Name the allotrope.
- other than carbon which shows allotropy
- which is known to form the largest number of compounds
What is meant by (i) elements (ii) compounds, and (iii) mixtures ?Write down the names of two elements, two compounds and two mixtures.
What are (i) metals (ii) non-metals, and (iii) metalloids ? Give two examples each of metals, non-metals and metalloids.
Classify the following into metals, non-metals and metalloids:
Silicon, Mercury, Diamond, Sulphur, Iodine, Germanium, Sodium, Carbon, Magnesium, Copper, Boron, Helium
Out of a colloid, solution and a suspension :
which one has the smallest particles ?
What is the concentration of a solution which contains 16 g of urea in 120 g of solution ?
Classify the following into true solutions and colloidal solutions:
Ink, Salt solution, Starch solution, Blood, Sugar solution
100 mL of water at room temperature of 25°C is taken in a beaker and a little of solid S is dissolved in it by stirring to obtain a solution X. More and more of solid S is added to the solution with constant stirring, while keeping the temperature of solution constant at 30°C. After some time it is observed that no more solid dissolves in water and at the same time some solid is also left undissolved at the bottom of the beaker.
- The contents of beaker are filtered through a filter paper to obtain solution Y in the form of a filtrate.
- What name is given to solutions like X ?
- What name is given to solutions like Y ?
- What will you observe if the solution Y at 30°C is cooled down to 10°C by keeping the beaker in crushed ice ? Why ?
- What term is used to denote the amount of solid dissolved in 100 grams of water in a solution lie Y ?
What is the general name of the process by which tea-leaves are separated from prepared tea ?
Draw a labelled diagram of the fractional distillation apparatus used for separating a mixture of alcohol and water.
Evaporation does form bubbles.
