1. Which of the following elements belongs to the s-block?
Answer:
Explanation:
Sodium is an alkali metal and belongs to the s-block.
2. Which alkaline earth metal is a major component of limestone?
Answer:
Explanation:
Limestone primarily consists of calcium carbonate (CaCO3).
3. Which s-block metal is stored under kerosene?
Answer:
Explanation:
Potassium is highly reactive with air and water, so it's stored under kerosene to prevent reactions.
4. Which of the following is not a property of s-block elements?
Answer:
Explanation:
s-block elements generally have low electronegativity.
5. Which gas is evolved when sodium reacts with water?
Answer:
Explanation:
Sodium reacts with water to release hydrogen gas.
6. Which element of the s-block is the lightest metal?
Answer:
Explanation:
Among metals, lithium has the lowest density, making it the lightest metal.
7. The metal used in aircraft construction due to its light weight is:
Answer:
Explanation:
Magnesium has a favorable strength-to-weight ratio, making it suitable for aircraft construction.
8. Which metal is responsible for the red color in fireworks?
Answer:
Explanation:
Strontium salts produce a red flame, often used in fireworks.
9. Which alkali metal has the highest atomic weight?
Answer:
Explanation:
Among the alkali metals, cesium has the highest atomic weight.
10. Which s-block element is not found free in nature due to its high reactivity?
Answer:
Explanation:
Due to its high reactivity, barium is not found in a free state in nature.
11. Which metal is present in green plants and aids in the process of photosynthesis?
Answer:
Explanation:
Magnesium is present in chlorophyll, the green pigment in plants responsible for photosynthesis.
12. Which s-block metal is used in photoelectric cells?
Answer:
Explanation:
Cesium is used in photoelectric cells due to its ability to emit electrons when exposed to light.
13. The s-block element with the lowest melting point is:
Answer:
Explanation:
Among the known s-block elements, francium has the lowest melting point.
14. The alkaline earth metal that imparts a brick-red flame is:
Answer:
Explanation:
Strontium salts impart a brick-red color to the flame.
15. Epsom salt is a salt of:
Answer:
Explanation:
Epsom salt is magnesium sulfate (MgSO4·7H2O).
16. Which of the following elements has the highest metallic character?
Answer:
Explanation:
Francium, being at the bottom of the alkali metal group, exhibits the highest metallic character.
17. Which alkaline earth metal is radioactive?
Answer:
Explanation:
Radium is a radioactive alkaline earth metal.
18. The s-block element used as a neutron absorber in nuclear reactors is:
Answer:
Explanation:
Lithium, especially in the form of lithium-6, is used as a neutron absorber in nuclear reactors.
19. The compound responsible for the hardening of water is a salt of:
Answer:
Explanation:
Calcium salts, like calcium carbonate, are responsible for the hardening of water.
20. The s-block metal that forms a superoxide when exposed to excess oxygen is:
Answer:
Explanation:
Potassium forms superoxide (KO2) when exposed to excess oxygen.