Chhattisgarh State Class 9 Science Chapter 8 Solution

Chhattisgarh State Board Class 9 Science Chapter 8 Chemical Bonding Exercise Multiple Choice, Fill in the Blanks, Questions and Answers here.

Chhattisgarh State Class 9 Science Chapter 8 Solution

1) Choose the correct option

(i) When sodium reacts with chlorine

(a) Each sodium atom accepts an electron

(b) Each chlorine atom accepts an electron

(c) Each sodium atom loses seven electrons

(d) Each chlorine atom loses seven electrons.

Ans: – option (b).

(ii) A sodium atom and a sodium ion:

(a) Are chemically same

(b) Have the same number of protons

(c) Form covalent bonds

(d) Have the same number of electrons.

Ans: – Option (b).

(iii) An ionic bond is formed when

(a) The combining atoms accept electrons

(b) The combining atoms lose electrons

(c) One atom loses and the second gains electrons

(d) When two metals react.

Ans: – option (c).

(iv) Which of the following elements loses two electrons in order to attain inert gas configurationsimilar to argon?

(a) magnesium (b) sodium

(c) calcium (d) sulphur.

Ans: – option (c).

(v) double bonds are found in which of the following molecules:

(a) N2

(b) C2H2

(c) Cl2

(d) CCl4.

Ans: – option (b).

2) Fill in the blanks

(i) Sodium atom ….loses…….. an electron to attain the electronic configuration of the element …. Neon…….

(ii) Two atoms of nitrogen share ……..three ………. pairs of electrons to form a nitrogen molecule.

(iii) The number of electrons in the outermost shells of inert gases is ………… eight………. but in caseof helium, it is ……… two……………..

(iv) Chlorine molecule has ……. covalent……….. bond but magnesium chloride has …. ionic……………… bond.

3) What type of bond is formed when electrons are transferred from one atom to another? Explain.

Ans: – The bond which formed by transferring of one electron to the other atom is known as ionic bond. The ionic bond always formed between a metal and non-metal. The excess electron was taken by the other atom to form the compound.

4) Draw the electron dot structure of a molecule that has a triple bond.

Ans: –

5) Argon atoms does not form Ar2 molecule by covalent bonding. Why?

Ans: – The outer most shell if filled with the electron then that element will not from any molecules. As the outer most shell of Argon is filled with the electron this element doesn’t form Ar2 molecules.

6) The electronic configuration of elements X and Y are:

X = 2,8,8,2 Y = 2,6

Explain the type of bonding seen when X and Y combine. Show through electron dot structures.

Ans: – Here X and Y will from ionic bond because one is metal (X) and other is non-metal (y).

7) What is the role of valence electrons in the formation of chemical compounds? Explain.

Ans: –  The valence electron of any elements is connected loosely by the bond energy. This valence electron takes part in the formation of bond by accepted of the other atoms.So, the chemical reaction happens because of the valance electron.

8) (i) Give the number of covalent bonds in one molecule of ammonia.

Ans: – The ammonia or NH3 are connected by the three covalent bonds with the nitrogen and hydrogen.

(ii) ‘Sodium chloride is a molecule’. Explain why this statement is not true.

Ans: – The sodium chloride doesn’t call as the molecules. The Na and Cl are made the ionic bond between them for making this compound. And for this reason, the sodium chloride is known as the ionic compound.

9) Draw the electron dot structures of the given compounds and write the type of bonding seen ineach.

(i) Water (ii) nitrogen

(iii) magnesium oxide (iv) calcium oxide.

Ans: –

10) Write down the properties of ionic and covalent compounds.

Ans: –

Ionic compounds  Covalent compounds
The compound has high melting point. It has low melting point.
It has high enthalpies of fusion. Has low enthalpies of fusion.
This type of compounds is hard. This type of compounds is soft.

11) Explain how the valency of an element is related to its electronic configuration.

Ans: – The valence is determined by the electronic configuration of the elements. The electronic configuration of the outermost shell of an element is explain the valency of that elements. It tells us that how much electron are needed to remove for making the compound.

12) The atomic numbers of three elements are 6,7 and 8 respectively.

(i) Write the electronic configuration of each element and give their valency.

Ans: – The electronic configuration of the elements is (2, 4); (2, 5); (2, 6). So, the valency of the compound is 4, 3, 2.

(ii) What type of compounds (ionic/covalent) will be formed by each of the elements? Explain.

Ans: – The compound which have this atomic number is carbon, nitrogen, oxygen. So as this are non-metal in nature this will form the covalent compounds.

13) Separate ionic compounds and covalent compounds in the given group. Give reasons for yourchoice.

Ans: – The ionic and covalent compounds will be separated by their dissolving in water. The compounds which is ionic will be dissolved in water whereas the compound of covalent bond will not dissolve in water.

14) Which of the following are possible? Give reasons for your answer.

(i) Mg2.  (ii) MgCl2.    (iii) Cl2.

Ans: – The Mg2 compound is not possible because this such form of metal is not seen in nature. And any type of bonding like ionic, covalent doesn’t fit in there. The other is possible because MgCl2 are connected with the ionic bond and Cl2 are connected with the electron sharing.

Updated: January 6, 2022 — 2:51 pm

3 Comments

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  1. CG Raipur kera road
    Sanjay Nagar birra

  2. You have to search some answers for the book

  3. Very helpful website thankyou your Help

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