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Name:__________________________________________________ Date:___________

Class:_________ Mr. Wolin (Science)

CHEM TEST: BONDING (H)

PART 1: Multiple Choice [66%]

|1) |Which of these elements has an atom with the most stable outer electron configuration? |

|A |(A) Ne (B) Cl (C) Ca (D) Na (E) Mg1+ |

|2) |The degree of polarity of a chemical bond in a molecule of a compound can be predicted by determining the difference in the |

|C |(A) melting points of the elements in the compound |

| |(B) densities of the elements in the compound |

| |(C) electronegativities of the bonded atoms in a molecule of the compound |

| |(D) atomic masses of the bonded atoms in a molecule of the compound |

| |(E) diameters of the bonded atoms in a molecule of the compound |

|3) |The balanced equation below represents a molecule of bromine separating into two bromine atoms. |

|B |What occurs during this change? |

| | |

| |(A) Energy is absorbed and a bond is formed. |

| |(B) Energy is absorbed and a bond is broken. |

| |(C) Energy is released and a bond is formed. |

| |(D) Energy is released and a bond is broken. |

| |(E) A more stable configuration is achieved |

|4) |Which Lewis electron-dot diagram is correct for CO2? |

|C | |

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|5) |Compared to a calcium atom, the calcium ion Ca2+ has |

|E |(A) more protons (B) fewer protons (C) more electrons (D) an incomplete octet (E) fewer electrons |

|6) |What is the correct Lewis electron-dot structure for the compound magnesium fluoride? |

|C | |

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|7) |Given the Lewis electron-dot diagram: |

|C |Which electrons are represented by all of the dots? |

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| |(A) the carbon valence electrons, only |

| |(B) the hydrogen valence electrons, only |

| |(C) the carbon and hydrogen valence electrons |

| |(D) all of the carbon and hydrogen electrons |

| |(E) all of the valence electrons and core electrons |

|8) |Which type of bond exists between an atom of carbon and an atom of fluorine? |

|C |(A) ionic (B) metallic (C) polar covalent (D) nonpolar covalent (E) polar covionic |

|9) |Which type of substance is soft, has a low melting point, and is a poor conductor of heat and electricity? |

|B |(A) network solid (B) molecular solid (C) metallic solid (D) ionic solid (E) silicon dioxide |

|10) |A diamond is an example of |

|D |(A) a supercooled liquid (B) an ionic compound (C) a metallic substance (D) a network solid (E) bling |

|11) |Which molecule contains a nonpolar covalent bond? |

|C | |

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|12) |Conductivity in a metal results from the metal atoms having |

|E |(A) high electronegativity |

| |(B) high ionization energy |

| |(C) highly mobile protons in the nucleus |

| |(D) A ratio of protons to neutrons greater than 1.7 |

| |(E) highly mobile electrons in the valence shell |

|13) |Which formula represents a nonpolar molecule containing polar covalent bonds? |

|E |(A) H2O (B) CO (C) NH3 (D) H2 (E) CCl4 |

|14) |At STP, fluorine is a gas and bromine is a liquid because, compared to fluorine, bromine has |

|B |(A) stronger covalent bonds |

| |(B) stronger intermolecular forces |

| |(C) weaker covalent bonds |

| |(D) weaker intermolecular forces |

| |(E) nonpolar covalent bonds |

|15) |Which Lewis electron-dot diagram is correct for a S2– ion? |

|D | |

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|16) |Which bond is least polar? |

|D |(A) As–Cl (B) Bi–Cl (C) P–Cl (D) N–Cl (E) Ar |

|17) |Which structural formula represents a polar molecule? |

|A | |

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|18) |Which statement explains why low temperature and high pressure are required to liquefy chlorine gas? |

|E |(A) Chlorine molecules have weak covalent bonds. |

| |(B) Chlorine molecules have strong covalent bonds. |

| |(C) Chlorine is a polar molecule |

| |(D) Chlorine molecules have strong intermolecular forces of attraction. |

| |(E) Chlorine molecules have weak intermolecular forces of attraction. |

|19) |Which of the following compounds has the highest boiling point? |

|A |(A) H2O (B) H2S (C) H2Se (D) H2Te (E) H2 |

|20) |Based on electronegativity values, which type of element tends to have the greatest attraction for electrons in a bond? |

|E |(A) metals (B) metalloids (C) group 1 elements (D) noble gases (E) nonmetals |

|21) |If the electronegativity difference between the elements in compound NaX is 2.1, what is element X? |

|A |(A) bromine (B) chlorine (C) fluorine (D) oxygen (E) Na |

|22) |Which substance contains bonds that involved the transfer of electrons from one atom to another? |

|C |(A) CO2 (B) NH3 (C) KBr (D) Cl2 (E) NaMg |

|23) |In aqueous solution, a chloride ion is attracted to which end of the water molecule? |

|A |(A) the hydrogen end, which is the positive pole |

| |(B) the hydrogen end, which is the negative pole |

| |(C) the oxygen end, which is the positive pole |

| |(D) the oxygen end, which is the negative pole |

| |(E) Chloride ions are not attracted to water molecules |

|24) |Which is the correct electron-dot formula for a molecule of chlorine? |

|D | |

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|25) |Which compound contains both ionic and covalent bonds? |

|C |(A) ammonia (B) methane (C) sodium nitrate (D) potassium chloride (E) NH3 |

|26) |Electron affinity is a measure of the tendency of an element to |

|A |(A) gain electrons (B) gain protons (C) lose electrons (D) lose protons (E) form ions |

|27) |The bond between which elements exhibits the greatest ionic character? |

|C |(A) chlorine and fluorine |

| |(B) lithium and fluorine |

| |(C) potassium and fluorine |

| |(D) sodium and fluorine |

| |(E) carbon and oxygen |

| |Base your answer to questions 28 - 29 on the table below. Consider the shell electron configuration of five elements. |

|28) |The most electronegative element is |

|B |(A) I (B) II (C) III (D) IV (E) V |

|29) |Which combinations would yield a compound with the most ionic character? |

|C |(A) I and II (B) I and III (C) II and IV (D) II and V (E) III and IV |

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|30) |The element which forms the most ionic bond with fluorine is |

|C |(A) Be (B) Ca (C) K (D) Li (E) Mg |

|31) |A bond between which types of elements will be covalent? |

|B |(A) two metals with a high electronegativity difference |

| |(B) two nonmetals with a very low electronegativity difference |

| |(C) a metal and nonmetal with high electronegativity difference |

| |(D) a metal and nonmetal with a low electronegativity difference |

| |(E) a metalloid and a nonmetal with a high electronegativity difference |

|32) |The main attractive force between polar molecules is |

|B |(A) ionic bonding |

| |(B) dipole attraction |

| |(C) hydrogen bonding |

| |(D) van der Waals attractions |

| |(E) molecule–ion forces |

|33) |The heat of vaporization of water is almost five times greater than that of oxygen, demonstrating that water |

|C |(A) evaporates more readily than oxygen. |

| |(B) molecules have more mass than oxygen molecules. |

| |(C) has forces between molecules that are greater than those between oxygen molecules. |

| |(D) has forces within molecules that are smaller than those within oxygen molecules. |

| |(E) is more likely to be found in the gaseous form than oxygen. |

PART 2: [34%]

1) Carbon dioxide is a non-polar molecule that contains polar covalent bonds

a) What is the electronegativity of Carbon? 2.6

b) What is the electronegativity of Oxygen? 3.5

c) Prove, mathematically, that the bonds in Carbon dioxide (CO2) are polar covalent.

Eneg of C = 2.6, eneg of O = 3.5 (( 3.5 – 2.6 = .9 (( less than 1.7 is polar covalent

b) Explain, in terms of structure and/or distribution of charge, why CO2 is a nonpolar molecule.

The molecule contains polar bonds, but the molecule is symmetrical, the charge distribution cancels

Out, making the whole molecule nonpolar

2) Answer the following questions with regard to water (H2O), whose structural diagram is shown below,

and your knowledge of chemistry.

(-

(+

a) What kind of bonds exist between the H and O atoms of this molecule? Polar covalent

Prove it and show your work!

Eneg of C = 2.1, eneg of O = 3.5 (( 3.5 – 2.1 = 1.4 (( less than 1.7 is polar covalent

b) In the diagram above, write in “(+” and “(-“ to indicate the positive and negative poles of

the water molecule

c) Explain, in terms of molecular structure or distribution of charge, why a molecule of water (H2O)

is polar.

water is a bent molecule (asymmetrical), the charge is distributed unequally throughout the molecule,

negative towards the oxygen end, more positive towards the hydrogen end.

d) H2O has a much higher boiling point than H2S. Explain, in terms of intermolecular bonding, why this

is the case.

H2O exhibits hydrogen bonding, which is a strong intermolecular force of attraction.

H2S does not exhibit hydrogen bonding, therefore less attraction between molecules

The greater the force of attraction between molecules, the higher the boiling point of the substance

3) Complete the following diagram by drawing in at least four “-“ to represent

electrons as they would be distributed in a molecule of HCl.

4) Base your answer to the following question on the table below.

a) Which substance is nonpolar hydrogen

b) Which substance has the most ionic bond? HCl

c) Which of the above substances has the weakest intermolecular bonds? hydrogen

d) Based on the information above, and your knowledge of chemistry, E

what is the boiling point of H-F

(A) 12 K (B) 169 K (C) 203 K (D) 240 K (E) 293 K

5) Within the spaces below

a) Draw the Lewis dot diagrams of the following molecules.

b) Determine whether the molecule is polar or nonpolar

| |a) H2O |b) PBr3 |

| | | |

| |polar |Polar |

|Shape |Molecular shapes Not on this test |Molecular shapes Not on this test |

| | | |

| |c) SO3 |d) HCN |

| | | |

| |nonpolar |polar |

|Shape |Molecular shapes Not on this test |Molecular shapes Not on this test |

6) Answer the following questions based on the chart below.

a) At what temperature does ethanol boil? 80(C

b) Which substance shown above has the weakest intermolecular bonding? propanone

c) At what temperature will water boil if the pressure is 120 kpa? 105(C

Molecular geometry

-----------------------

(A)

[2]

[2]

(B)

(C)

(D)

(D)

(C)

(B)

(A)

(D)

(C)

(B)

(A)

(D)

(C)

(B)

(A)

(D)

(C)

(B)

(A)

B and C both contain nonpolar covalent bonds

(E)

(D)

(C)

(B)

[2]

Cl

H

For Teacher Use Only

[2]

[2]

[1]

[1]

O

H

H

[1]

[1]

[1]

[1]

For Teacher Use Only

(E) none of the diagrams are correct

(E) none of the diagrams are correct

(A)

[1]

[1]

[1]

[2]

[1]

For Teacher Use Only

None of the diagrams are correct

(E)

B and C are both polar molecules

(E)

Both C and D

are correct

(E)

[4]

[2]

[2]

[4]

Br

Br

Br

P

O

O

O

S

H

N

C

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