Tutor Marked Assignment
CHE-01: Atoms and Molecules
Course Code: CHE-01
Assignment Code: CHE-01/TMA/2018
Maximum Marks: 100
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ASSIGNMENT BOOKLET
Bachelor’s Degree Programme (B.Sc.)
ATOMS AND MOLECULES
(Valid from 1st January, 2018 to 31
st December, 2018)
1. a) Describe the common features which can be explained by the theoretical model of Bohr?
Briefly write the limitation of this model.
(5)
b) Calculate the ionization energy of hydrogen atom using Bohr’s theory. (5)
2. a) Derive an expression for calculating energy values corresponding n = 3 for a particle in
one dimensional box.
(5)
b) Write the values of four quantum numbers for 3d electrons. (5)
3. a) Explain the reason for the variation of the first ionization energies of the third period
elements.(4)
b) Calculate the lattice energy for ZnO crystal using Eq. 3.4 based on
electrostatic model and using a Born-Haber cycle. Compare the two answers and comment
on any difference.
Useful data:
(6)
4. a) In carbonate ion, all the three CO bonds have identical bond length. Explain. (4)
b) Explain the type of hybridization in phosphorous pentafluoride. (6)
5. a) By writing molecular orbital configuration for each of following molecules calculate the
bond order and also determine whether it is paramagnetic or diamagnetic.
(i) NO (ii) CO (iii) O2
+
(6)
b) Using suitable examples define gerade and ungerade orbitals. (4)
6. a) The dipole moment of HBr is 2.60 10 30 C m and interatomic distance 141 pm. What is
the percentage ionic character of HBr?
(6)
b) Draw all of the stereoisomers of 2,3-butandiol, label meso compounds and pairs of
enantiomer.
(2)
c) What is the predicted magnetic moment of Cu+
and Cu2+ ions in B Unit (Atomic number
of Cu 29)?
(2)
7. a) Given that the spacing of the lines in the microwave spectrum of 24Al1H is constant at
12.604 cm 1
. Calculate the moment of inertia and bond length of the molecule.
(6)
4
b) Determine the wavelength for a transition from the = 0 to the = 1 level. Is this
transition in the IR region of the electromagnetic spectrum?
(2)
c) Which of the following molecules exhibit rotational and or vibrational spectra
H2, HF, CO, NO
(2)
8. a) From the infrared spectrum given below, identify the possible functional groups
corresponding to the peaks indicated in the arrows.
(4)
b) Explain why
*
transitions are the most useful transition in UV VIS spectroscopy? (3)
c) UVVIS absorption spectra are broad band spectra. Explain. (3)
9. a) Normal water contains isotope of hydrogen 3H, tritium. It has a half-life of 12.3 years.
Determine the age of a bottle of wine whose 3H radiations is about 1/10 that present in
new wine.
(5)
b) Complete following equations: (5)
i)
P … Si 30 30
ii)
B
10 n
iii)
Ne Ba Dy ….
20 136 150
iv) … H Na
2 22
v)
Am … Bk 2n
241 243
10. a) Arrive at the Lewis structure of XeF4 using the steps given in Unit 3. (4)
b) Predict the hybridization state of each carbon atom in allene which has the following
structure:
CH2 = C = CH2
(3)
c) Calculate the number of normal modes of vibration for the following compounds: (3)
i) H2O
CH4
ii) HBr
Thankx