General Science
6th Class
Chapter 6
Elements and Compounds
Questions
6.1 Encircle the correct option.
1. Which one of the following is a metallic element?
a. hydrogen b. helium c. lithium d. carbon
2. Which one of the following is a non-metallic element?
a. iron b. aluminium c. beryllium d. oxygen
3. Which one of the following is a metalloid element?
a. gold b. boron c. silver d. nitrogen
4. Choose an atom which can exist independently at room temperature?
a. Cu b. Na c. O d. Ne
5. How many hydrogen atoms are present in 1 molecule of ammonia?
a. 1 b. 2 c. 3 d. 4
6. How many atoms are present in one molecule of helium?
a. 1 b. 2 c. 3 d. 4
7. C6H12O6 is the formula of glucose. How many oxygen atoms are there in one molecule of glucose?
a. 3 b. 6 c. 9 d. 12
8. Which one of the following is an element?
a. O3 b. CO2 c. CH4 d. H2O
9. Number of neutrons in helium atom:
a. 1 b. 2 c. 3 d. 4
10. 
a. an atom b. an element c. a compound d. none of these
11. Water, carbon dioxide, ammonia and methane are examples of:
a. atoms b. elements c. compounds d. mixtures
12. Hydrogen, helium, carbon, nitrogen and oxygen are examples of:
a. atoms b. elements c. compounds d. mixtures
6.2 Write short answer.
1. Define element.
Ans.
An element is a substance which consist of only one kind of atoms. It is simplest form of matter.
2. Write the names and symbols of any two metals.
Ans.
Magnesium Mg and Iron Fe.
3. Write the names and symbols of any four non-metals.
Ans.
Hydrogen H, Nitrogen N, Neon Ne, Oxygen O.
4. Write names and symbols of any three noble gases.
Ans.
Neon Ne, Argon Ar, Krypton Kr.
5. Write the names and formulae of any five compounds.
Ans.
Ammonia NH3, Sodium chloride NaCl, Glucose C6H12O6, Methane CH4, Carbon dioxide CO2.
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