Some Examples of the Chemical Bonding Concept Test

ELECTRONIC SUPPLEMENTAL MATERIALS

Some examples of the chemical bonding concept test

PART A

1. CH4 is a;

A) polar molecule B)nonpolar molecule

Because:

1. Carbon atom has a nonbonding electron pairs
2. Electrons are not shared between C ve H equally
3. CH4 dissolves in water.
4. Four H atoms pull on the central C atom.

2. Ammonia (NH3) and nitrogen trifluoride (NF3) have similar chemical formulas and structures. However; the boiling point of NH3 is higher than that of NF3. The reason of this is;

A)intermolecular bonds B) intramolecular bonds

Because:

1. The bonds of NF3 can be broken easily while those of NH3 cannot.
2. The Van der Waals forces of NH3 are stronger than those of NF3
3. There are hydrogen bonds in NH3 molecule
4. While NH3 contains ionic bonds NF3 contains covalent bonds

3. How is the shape of BF3 molecule?

A) B)

Because:

1. Nonbonding electrons on B repel bonding electrons
2. Bonding electrons arrange based on decreasing interaction of electrons
3. Fluorine has a stronger attraction for the bonding electrons
4. Electrons are shared between B and F equally

PART B

4. Which of the following sentence wrong about the chemical bonding?

A)Ionic bonds are stronger than covalent bonds.

B)Atoms are more stable when forming covalent bonds

C)The energy releasing when the bonds forming is equal to that of required to breaking bonds

D)The energy of bonds is the measure of bond strength

E)The forming bonds is endothermic process

A)I-III B) II-IV C) I-II-IV D) III-IV E) I-III-IV

5. Which are the correct related to elements of 1H, 7N, 8O, 9F?

1. NH3 is a polar molecule
2. HF is a non-polar molecule
3. H2O is a polar molecule
4. NF3 is a non-polar molecule

A)I-III B) I-II-III C) I-IV D) III-IV E) II –IV

OBSERVATION CHECKLIST