Student’s Name : Date:
TEST # 2
| Knowledge / Understanding | Thinking/Inquiry | Communication | Application | Marks |
| 12 | 12 | 8 | 12 | 44 |
Part A: Multiple choice ( Knowledge/ Understanding 15×1=15)
———-. 1. The 3p atomic orbital has the shape of
a. a sphere b. a torus
c. a dumb- bell d. two perpendicular dumb bells
———- 2. Which of the following examples of bond hybridization best accounts for the shape of the molecule shown below
a. sp b.sp2
c. sp3 d. none of the above
———– 3. Why do energy levels exist in atoms?
a. electrons are negatively charged b. electrons are attracted to certain numbers of neutrons
c. electrons are only able to possess quanta of energy
d. electrons will display only certain colors
———– 4. Which feature of atomic structures was discovered the earliest?
a. the electron b. the protons
c. the nucleus d. the orbit
———– 5. Chemical bonding can best be prepared and explained by the properties of
a. valence electrons b. inner core electrons
c. the effective nuclear charge d. the atomic radius
————- 6. Which of the following is an example of an intermolecular force?
a. hydrogen bond b. covalent bond
c. ionic bond d. metallic bond
————– 7. A substance that has a melting point of 18500C and a boiling point of 2700 0C is insoluble in water and is a good electrical insulator. The substance is most likely
- An ionic compound b. a net work solid
- A polar covalent compound d. a molecular solid
————— 8. VSEPR theory allows you to predict
a. the polarity of a simple molecule b. whether a compound is ionic or molecular
c. the shape of a molecule around a central atom
d. the lewis structure
—————- 9. Which statement is best description of potassium chloride?
a. polar molecule b. polar bond non polar molecule
c. ionic compound d. non polar molecule
———– 10. What is the bond angle in a trigonal planar molecule?
- 900 b. 104.50
c.1070 d. 1200
———— 11. Which of the following does not have an electron configuration ending with 3s23p6?
a. chloride ion b. sulphide ion
c. aluminum ion d. calcium ion
———- 12. What molecular shape is shown below?
a. trigonal planar b. tetrahedral
c. bent d. trigonal pyramidal
PART B. ( THINKING/ INQUIRY: 12)
1. Indicate whether each statement is true or false. If you think the statement is false, rewrite it to make it true. ( T/I= 3)
i. The chemical properties of an atom mainly results from its protons.
ii. Energy is quantized and can only occur in discrete units.
iii. In an expanded valence , with stability, a central atom has more than eight valence electrons.
2. . Explain why:
i. Calcium has a higher melting point than Magnesium.
ii. The ionic radius of P3- is Greater than the ionic radius of Si4+. (T 2+2)
3. Do hybridized orbitals exist in isolated atoms? Why or why not? ( T=2)
4. Use VSEPR theory and bond polarity calculations to predict if boron trifluoride BF3, is a polar molecule? ( I=3)
PART C ( COMMUNICATION 8)
1. Provide a set of four quantum numbers for the 22nd electron in Chromium.( 3)
2.Explain why electrons in the outermost shell of an atom are considered different and given the term valence electrons? ( Comm 2)
3. Define Hund’s rule.(Comm 1)
4. Draw an energy diagram for fluorine. ( Comm.2)
PART D ( APPLICATION 12)
1. . What happens when the electronegativity difference between 2 atoms is very large? (App 2)
2. Write the electron configuration of copper. Explain. ( 2)
3. How are sigma and Pi bonds formed? ( App 2)
4. Why the bond angle in water is lesser than expected value? ( 2)
5. Draw the Lewis structure for the molecule Nitrate ion (NO3—. )( 2)
6. Predict whether Carbon tetrachloride molecule is polar or non polar.( 2)
