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 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 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 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, sp2, 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 2px
(c) 2py and 2py
(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: O2, O2+, O2- (superoxide), O22-(peroxide)
Question 38
Describe the hybridisation in case of PCl5. Why are the axial bonds longer as compared to equatorial bonds?
Question 40
What is meant by the term bond order? Calculate the bond order of: N2, O2,O2+,and O2-.