SAT Subject Test Chemistry

PART 2

REVIEW OF MAJOR TOPICS

CHAPTER 3

Bonding

Practice Exercises

The following questions are in the format that is used on the SAT Subject Area Test in Chemistry. If you are not familiar with these types of questions, study before doing these review questions.

Directions: The following set of lettered choices refers to the numbered questions immediately below it. For each numbered item, choose the one lettered choice that fits it best. Then fill in the corresponding oval on the answer sheet. Each choice in the set may be used once, more than once, or not at all.

Questions 1–7

(A) ionic

(B) covalent

(C) polar covalent

(D) metallic

(E) hydrogen bonding

1. When the electronegativity difference between two atoms is 2, what type of bond can be predicted?

2. If two atoms are bonded in such a way that both members of the pair equally share one electron with the other, what is the bond called?

3. Which of the five choices is considered the weakest bond in the group?

4. Which of the above bonds explains water’s abnormally high boiling point?

5. If the sharing of an electron pair is unequal and the atoms have an electronegativity difference of 1.4 to 1.6, what is this type of sharing called?

6. If an electron is lost by one atom and completely captured by another, what is this type of bond called?

7. If one or more valence electrons become detached from the atoms and migrate in a “sea” of free electrons among the positive metal ions, what is this type of bonding called?

Directions:

Every question below contains two statements, I in the left-hand column and II in the right-hand column. For each question, decide if statement I is true or false and whether statement II is true or false, and fill in the corresponding T or F ovals in the answer spaces. *Fill in oval CE only if statement II is a correct explanation of statement I.

I

 

II

8. Maximum repulsion between two electron pairs in a molecular compound will result in a linear structure

BECAUSE

the VSEPR model says that like charges will orient themselves so as to diminish the repulsion between them.

9. Sodium chloride is an example of ionic bonding

BECAUSE

sodium and chlorine have the same electronegativity.

10. Ammonia has a trigonal pyramidal molecular structure

BECAUSE

ammonia has a tetrahedral electron pair geometry with three atoms bonded to the central atom.

*Fill in oval CE only if II is a correct explanation of I.

Answers and Explanations

1. (A) When the electronegativity difference between the two atoms is greater than 1.7, the bond between them is considered more than 50% ionic.

2. (B) When two atoms equally share a pair of electrons, the bond is considered covalent. With an electronegativity difference of 0 to 0.3, the bond is still considered covalent.

3. (E) Hydrogen bonding is the weakest because it is the weak attraction of the hydrogen end of a polar molecule to the partial negative charge of an adjacent molecule. Especially strong in water, it is responsible for many of water’s properties.

4. (E) Because of the strong hydrogen bonding in water, it takes much more energy to cause the molecules to break away from each other in the liquid state and change to steam.

5. (C) When the electronegativity difference between the two bonding atoms is between 0.3 and 1.7, the electrons are not equally shared and result in a polar covalent bond.

6. (A) This is the definition of a pure ionic bond.

7. (D) Metallic bonds are defined as a “sea” of free electrons that migrate through the metal.

8. (T, T, CE) The mutual repulsion of two electron clouds forces them to the opposite sides of a sphere. An example is BeF2, which forms a linear molecular structure like this, F – Be – F.

9. (T, F) The bond between sodium and chlorine in sodium chloride is ionic, because the difference between their electronegativity is greater than 1.7.

10. (T, T, CE) The molecular structure of NHis a trigonal pyramidal structure like this.