Question 1 - (10 Marks)

For the following descriptions of molecules, draw the Lewis structure of the molecule and show all bond angles (assuming ideal VSEPR angles).

a) (5 marks) - An organic compound with the molecular formula H3CNO. Both C and N are sp² hybridized while O is sp³ hybridized. There are two possible isomers of this compounds, you need only draw one of them.

b) (5 marks) 一 An organic compound with the molecular formula H3CNO. Both C and O are sp² hybridized while N is sp³ hybridized.

Question 2 - (10 Marks)

This question is based on the five compounds (A-E) given below.

(A) CH3-CH2-CH3

(B) CH3-CHBr-CH3

(C) CH3-CH2-CH2Br

(D) CH3-CH2-C(Br)(CH3)- CH3

(E) CH3-CH2-CBr=CBr-CH2-CH3

1. Label compounds A-E as either saturated or unsaturated.

2. Which of the compounds, A-E are constitutional isomers of each other?

3. Which of the compounds, A-E, is/are optically active? Explain.

4. Would any of the five compounds react with Tollen's reagent or with 2,4- dinitrophenylhydrazine? Explain.

Question 3 - (10 Marks) - Use MO theory to explain the following:

i. The ionization energy of nitrogen (N) is ~1400 kJ/mol, while the ionization energy of dinitrogen (N2) is ~1500 kJ/mol.

ii. The ionization energy of hydrogen (H) is ~1300 kJ/mol and the ionization energy of fluorine (F) is ~1700 kJ/mol, while the ionization energy of hydrogen fluoride (HF) is ~1700 kJ/mol.

iii. When an electron is added to C2 to make the negatively charged ion, the bond length becomes shorter.

iv. What does the fact that both N2 and HF are colourless tell us about the orbital energies in the above diagrams?