test chm

TEST 1 (CHM361) 2013

TEST 1/CHM361

NAME :_______________________________________

GROUP : _______________________________________

LECTURE’S NAME:_______________________________________

PART A

1. The size of an element’s atomic radius __________ from left to right across the

periodic table.

a. increases b. decreases

c. remains constant d. is randomly assigned

2. For each of the following ions, which of the species is larger?

a. N3-

b. O2-

c. F-

d. Li+

3. What is the hybridization of the carbon atoms in benzene, C6H6?

a. sp3d

2 c. sp

3

b. sp2 d. sp

3d

4. Use VSEPR theory to predict the molecular geometry of ICl3.

a. triangular planar b. triangular pyramidal

d. t-shaped e. octahedral

5. The bond angle in Cl2O is expected to be approximately:

a. 90 o

b. 109.5 o

c. 120 o d. 145

o

6. Which statement is false? A sigma molecular orbital

a. may result from overlap of p atomic orbitals perpendicular to the molecular axis

(side-on).

b. may result from overlap of p atomic orbitals along the molecular axis (head-on).

c. may result from overlap of two s atomic orbitals.

d. may result from overlap of one s and one p atomic orbitals.

50

TEST 1 (CHM361) 2013

TEST 1/CHM361

PART B

QUESTION 1

a) Explain the pattern for electronegativity from the periodic table.

b) Which species of each pair has the higher ionization energy?

i) Mg or Mg2+

ii) O or O2-

iii) K+ or Cl

-

iv) P3-

or S2-

TEST 1 (CHM361) 2013

TEST 1/CHM361

c) Arrange the following ions in order of decreasing ionic radius.

i) Ar, Cl-, K

+, S

2-

ii) C, Al, F, Si

iii) Na, Mg, Ar, P

iv) I-, Ba

2+, Cs

+, Xe

QUESTION 2

a) Hybridization occurs to minimize electron repulsion when atoms are bought together

to form molecules. Describe the hybrid orbitals used by the central metal atom and the

type of bond formed in (CH2)2 molecules.

TEST 1 (CHM361) 2013

TEST 1/CHM361

b) Molecular orbitals are form when atomic orbitals overlap. Sketch the molecular

orbitals formed when atomic below interact.

i) Two 2py orbitals constructively

ii) Two 2pz orbitals destructively

iii) Two 2s orbitals destructively

c) For nitrogen gas (N2) molecule.

i) Construct a molecular orbitals diagram for the formation of N2 molecule.

TEST 1 (CHM361) 2013

TEST 1/CHM361

ii) Predict the HOMO and LUMO?

iii) Identify the bond order?

QUESTION 3

Given: Si2F4

a) Draw the lewis structure for Si2F4.

b) How many sigma and pi bond?

TEST 1 (CHM361) 2013

TEST 1/CHM361

c) Show the hybridization process/overlapping orbital diagram of Si2F4.

d) What is hybridization of central atom?

e) State the shape of compound formed.

f) State the angle for that compound.

test chm

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