Question 2 

Write Lewis dot symbols for atoms of the following elements: Mg, Na, B, O, N, Br.

Question 3
Write Lewis symbols for the following atoms and ions:
S and S2–; Al and Al3+; H and H–

Question 4
Draw the Lewis structures for the following molecules and ions: H2S, SiCl4, BeF2, , HCOOH

Question 7
Discuss the shape of the following molecules using the VSEPR model:
BeCl₂, BCl₃, SiCl₄, AsF₅, H₂S, PH₃

Question 9
How do you express the bond strength in terms of bond order?

Question 12
H₃PO₃ can be represented by structures 1 and 2 shown below. Can these two structures be taken as the canonical forms of the resonance hybrid representing H₃PO₃? If not, give reasons for the same.

Question 13
Write the resonance structures for SO₃, NO₂ and 

Question 14
Use Lewis symbols to show electron transfer between the following atoms to form cations and anions:
(a) K and S (b) Ca and O (c) Al and N.

Question 17
Define electronegativity. How does it differ from electron gain enthalpy?

Question 19
Arrange the bonds in order of increasing ionic character in the molecules: LiF, K₂O, N₂, SO₂ and ClF₃.

Question 21
Apart from tetrahedral geometry, another possible geometry for CH₄ is square planar with the four H atoms at the corners of the square and the C atom at its centre. Explain why CH₄ is not square planar?

Question 24
What is meant by hybridisation of atomic orbitals? Describe the shapes of sp, sp^₂, sp³ hybrid orbitals.

Question 26
Is there any change in the hybridisation of B and N atoms as a result of the following reaction?
BF₃ + NH₃ → F₃B.NH₃

Question 28
What is the total number of sigma and pi bonds in the following molecules?
(a) C₂H₂ (b) C₂H₄

Question 29
Considering x-axis as the internuclear axis which out of the following will not form a sigma bond and why?
(a) 1s and 1s
(b) 1s and 2p_x
(c) 2p_y and 2p_y
(d) 1s and 2s.

Question 30
Which hybrid orbitals are used by carbon atoms in the following molecules?
(a)CH₃–CH₃;
(b) CH₃–CH=CH₂;
(c) CH₃-CH₂-OH;
(d) CH₃-CHO
(e) CH₃COOH

Question 31
What do you understand by bond pairs and lone pairs of electrons? Illustrate by giving one example of each type.

Question 36

 Compare the relative stability of the following species and indicate their magnetic properties:  O_2, O2^+, O₂^- (superoxide), O₂^2-(peroxide)

Question 38
Describe the hybridisation in case of PCl₅. Why are the axial bonds longer as compared to equatorial bonds?

Question 39
Define hydrogen bond. Is it weaker or stronger than the van der Waals forces?

Question 40
What is meant by the term bond order? Calculate the bond order of: N₂, O₂,O₂⁺,and O₂^-.