Student Corner

1. The atomic number of four elements P, Q, R, S are 6, 8, 10 and 12 respectively. The two elements which can react to form ionic compounds are:
A. P and S
B. Q and R
C. P and R
D. Q and S
Ans. D
Explanation: Q atom’s electronic configuration is 2,4,2 and S atom is 2,4,6. Therefore Q has 2 electrons in its outer most shell, so it will lose 2 electrons to S and both will attain inert gas configuration.
2. Which of the following statement is true about ionic compounds?
A. Ionic compounds conduct electricity when dissolved in water.
B. Ionic compounds are not soluble in water.
C. Ionic compounds are crystalline solids.
D.  Only A and C
Ans. D
Explanation: Ionic compounds conduct electricity when dissolved in water or melted. They are soluble in water and are also crystalline solids.
3.The solution of one of the following compounds will conduct electricity. This compound is:
A. CCl4
B. HCl
C. CaCl2
D. CH3Cl
Ans. C
Explanation: CaCl2 form ionic bond and so will conduct electricity.
4. Which of the following property is not of ionic compound?
A. Solubility in water
B. High melting and boiling points
C. Electrical conductivity in solid state
D. Electrical conductivity in molten state
Ans. B
Explanation: Ionic compounds are soluble in water, conduct electricity in solid and molten state.
5. Which of the following compounds is not ionic in nature?
A. Lithium Chloride
B. Ammonium Chloride
C. Calcium Chloride
D. Carbon tetrachloride
Ans. D
Explanation: Except carbon tetrachloride all forms ionic bond.

6. Ionic compound are soluble in:
A. Ether
B. Alcohol
C. Kerosene
D. Water
Ans. D
Explanation: Ionic compounds are soluble in water but insoluble in organic solvents like ether, acetone, alcohol, kerosene oil etc.
7. What is an ionic bond?
A. Ionic bond is formed by sharing of electrons between two atoms.
B. It is a bond formed by the transfer of electrons from one atom to another.
C. Both A and B are correct
D. None of the above
Ans. B
Explanation: Ionic bond is formed by the transfer of electrons from one atom to another.
8. Name the ions present in Sodium Oxide compound?
A. Sodium ions
B. Oxide ions
C. Both A and B
D. Neither A nor B
Ans. C
Explanation: The ions present in Sodium Oxide compound are: Sodium ions and oxide ions.
9. Which of the following are electrovalent compounds?
A. Copper Sulphate
B. Calcium Nitrate
C. Magnesium Oxide
D. All of the above
Ans. D
Explanation: Electrovalent compound are ionic compounds and so all the options given in the question forms ionic bond.
10. What is the electronic configuration of calcium ion (Ca2+)
A. 2,8
B. 2,8,2
C. 2,8,4
D. 2,8,8
Ans. D
Explanation: The atomic number of calcium is 20 so its electronic configuration is 2,8,8,2 and so has 2 electrons in the outer most shell. Therefore to form calcium ion (Ca2+), calcium will lose 2 electrons and its configuration becomes 2,8,8.
From the above article we have learnt what are ionic compounds, how they are formed, what are the properties of ionic compounds etc.