MEDIUM
9th CBSE
IMPORTANT
Earn 100

Write the distribution of electrons in carbon and sodium atoms. 

Important Questions on Test Paper 4

MEDIUM
9th CBSE
IMPORTANT

Isotopes find important applications in a variety of areas in the fields of medicine, agriculture, generation of cheaper electricity, industry, radiocarbon dating, etc. 

a. Which isotope is used for detecting the thyroid disorder? 
b. Which isotope is used to monitor the uptake of phosphorus by plants? 
c. Which isotopes are used for the generation of cheaper electricity? 
d. Which isotope is used to test the complete removal of phosphorus from steel in the manufacture of steel? 
e. Which isotope is used for finding the age of a fossil? 

MEDIUM
9th CBSE
IMPORTANT
Define valency by taking examples of silicon and oxygen. 
MEDIUM
9th CBSE
IMPORTANT
Which separation techniques will you apply for the separation of the following mixtures? 
a. Sodium chloride from its solution in water. 
b. Ammonium chloride from a mixture containing sodium chloride and ammonium chloride. 
c. Small pieces of metal from the engine oil of a car. 
d. Benzene from a mixture of benzene and methylbenzene. 
e. Different pigments from an extract of flower petals. 
 
MEDIUM
9th CBSE
IMPORTANT
Calculate the mass of 
a. 1 atom of nitrogen 
b. 1 atom of silver 
c. 1 molecule of benzene (C6H6). 
 
MEDIUM
9th CBSE
IMPORTANT
How many molecules are present in 
a. 9 g of water 
b. 17 g of ammonia?
HARD
9th CBSE
IMPORTANT
Describe Bohr's model of atom. 
MEDIUM
9th CBSE
IMPORTANT
Give important applications of isotopes.
MEDIUM
9th CBSE
IMPORTANT
Write two differences between a true solution and a colloid.