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Name:__________________________________________________ Date:___________

Class:_________ Mr. Wolin (Science)

PRACTICE TEST: BONDING (R)

PART 1: Multiple Choice [70%]

|1 |Which of these elements does not have atoms with a stable outer electron configuration? |

|B |(A) Ne (B) Cl (C) Kr (D) Rn |

|2 |In a chemical bond, the difference between electronegativities of the atoms can be used to determine the |

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

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

| |(C) degree of polarity of the bond |

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

|3 |The balanced equation below represents two atoms of Bromine (Br) bonding to form a molecule of Bromine (Br2). |

|C |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. |

|4 |Draw the Lewis Dot Structure for Carbon dioxide (CO2) |

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

|D |(A) more protons (B) fewer protons (C) more electrons (D) 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? |

| | |

| |(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 |

|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 |

|9 |Which molecule contains a nonpolar covalent bond? |

|C | |

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|10 |Which type of substance is hard, 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 |

|11 |Conductivity in a metal results from the metal atoms having |

|D |(A) high electronegativity (C) highly mobile protons in the nucleus |

| |(B) high ionization energy (D) highly mobile electrons in the valence shell |

|12 |A diamond is an example of |

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

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

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

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

|B |(A) stronger covalent bonds (C) weaker covalent bonds |

| |(B) stronger intermolecular forces (D) weaker intermolecular forces |

|15 |Which element has an atom with the greatest attraction for electrons in a chemical bond? |

|C |(A) As (B) Bi (C) N (D) P |

|16 |Which Lewis electron-dot diagram is correct for a S2– ion? |

|D | |

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|17 |Which bond has the greatest degree of ionic character? |

|D |(A) H–Cl (B) I–Cl (C) Cl–Cl (D) K–Cl |

|18 |Which bond is least polar? |

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

|19 |Which structural formula represents a polar molecule? |

|A | |

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|20 |Which statement explains why low temperature and high pressure are required to liquefy chlorine gas? |

|C | |

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

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

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

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

|21 |Which of the following compounds has the highest boiling point? |

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

|22 |Based on electronegativity values, which type of elements tends to have the greatest attraction for electrons in a bond? |

|C |(A) metals (B) metalloids (C) nonmetals (D) noble gases |

|23 |Which is the correct electron-dot formula for a molecule of chlorine? |

|D | |

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|24 |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 |

|25 |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 (C) the oxygen end, which is the positive pole |

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

|26 |Which Lewis electron-dot diagram correctly represents a hydroxide ion? |

|A | |

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|27 |Which substance contains bonds that involved the transfer of electrons from one atom to another? |

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

|28 |Which compound contains both ionic and covalent bonds? |

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

PART 2: [30%]

29) Answer the following questions regarding CO2 and F2.

a) What kind of bond exists between an atom of C and O in CO2? Polar Covalent [3]

show your work!

b) What kind of bond exists between the F atoms in a molecule of F2? Non polar covalent_______________ [3]

show your work!

c) Based upon your work above, which bonds are more polar, C-O or F-F? C-O [3]

d) Explain, in terms of structure and/or distribution of charge, why CO2 is a nonpolar molecule. [3]

The molecule is symmetrical and there is an equal distribution of electrons in the molecule

30) 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 [3]

Show your work!

b) Explain, in terms of molecular structure or distribution of charge, why a molecule of water (H2O) [3]

is polar.

The molecule is asymmetrical

c) In the diagram above, write in “(+” and “(-“ to indicate the positive and negative poles of [3]

the water molecule

d) H2O has a much higher boiling point than H2S. Explain, in terms of intermolecular bonding, why this [3]

is the case. H2O has hydrogen bonding, H2S does not

31) Complete the following diagram by drawing in “-“ to represent [2]

electrons as they are distributed in a molecule of HCl.

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

Explain, in terms of molecular polarity and intermolecular forces, why hydrogen has a lower boiling point [1]

than hydrogen bromide.

Hydrogen is a nonpolar molecule and will not exhibit intermolecular forces between other hydrogen molecules

Hydrogen bromide is a polar molecule, it will exhibit intermolecular forces between other HBr molecules

Since HBr molecules have intermolecular forces, they will be attracted to each other

33) Base your answer to the following questions on the information below.

Carbon and oxygen are examples of elements that exist in more than one form in the same phase.

Graphite and diamond are two crystalline arrangements for carbon. The crystal structure of graphite is organized in layers. The bonds between carbon atoms within each layer of graphite are strong. The bonds between carbon atoms that connect different layers of graphite are weak because the shared electrons in these bonds are loosely held by carbon atoms. The crystal structure of diamond is a strong network of atoms in which the shared electrons are strongly held by the carbon atoms. Graphite is an electrical conductor, but diamond is not. At 25°C, graphite has a density of 2.2 g/cm3 and diamond a density

of 3.51 g/cm3.

The element oxygen can exist as diatomic molecules, O2, and as ozone, O3. At standard pressure the boiling

point of ozone is 161 K.

a) What is the boiling point of oxygen (O2) look it up in the reference tables [1]

b) Explain, in terms of intermolecular forces, the difference in the boiling points of O2 and O3 at standard [1]

pressure. Your response must include information about both O2 and O3.

O2 is nonpolar, no intermolecular forces

O3 is polar, has intermolecular forces

c) Explain, in terms of electrons, why graphite is an electrical conductor and diamond is not. [1]

Your response must include information about both graphite and diamond.

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Cl

H

(D)

(C)

(B)

(A)

(D)

(C)

(B)

(A)

(D)

(C)

(B)

(A)

(D)

(C)

(B)

(A)

(D)

(C)

(B)

(A)

(D)

(C)

(B)

(A)

Br + Br (( Br2

O

H

H

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