Come Together: Chemical Bonding Worksheet



Name KEY

Period Date

Chapter 6: Review

Bonding Comparison Chart

| |IONIC |COVALENT |METALLIC |

|Types of Atoms Involved |Metals and nonmetals |Nonmetals |Metals and metals |

|(Metal, Nonmetal) | | | |

|Method of |Positive ions bonding with negative|Sharing valence electrons |Valence electrons are shared among |

|Bond Formation |ions…Transfer of Electrons | |atoms…A Sea of Electrons |

|(Valence Electrons) | | | |

|Type of Structure |Crystalline |Molecular |Crystalline with electrons moving |

| | | |throughout all atoms |

|Physical State |Solid |Gases, liquids, or low melting point |Solid |

|(Solid, Liquid or Gas) | |solids | |

|Melting/Boiling Point |High melting point |Low melting point |High melting point |

|(High or Low) | | | |

|Solubility in Water? |Soluble |Insoluble / soluble |Low solubility |

|Electrical Conductivity ? |High (as liquid) |Does not conduct |Relatively high conductivity |

| |Low (as solid) | | |

|Other Properties |Most are hard |Flammable |Malleable |

CHAPTER 6 REVIEW

1. Why do most atom form chemical bonds?

Atoms form chemical bonds to minimize their potential energy

Atoms have high potential energy. Atoms bonded have lower potential energy.

2. What are the exceptions to the octet rule?

Exceptions are 1 ) HYDROGEN = 2 valence electrons

2) BORON = 6 valence electrons

3. Explain why some elements can have an expanded octet?

3rd period elements have access to the “d - block” which allows an expanded octet.

4. Explain why ionic compounds do not conduct electricity in their crystalline lattice form.

Electrons are “FIXED” in their solid forms positions.

5. Identify bond types as either ionic, metallic or covalent

HCN:__Covalent___ Fe: _Metallic___ PbO:_Ionic___ Si: _Covalent____

6. A molecule of which of the following compounds contains a double bond?

a) C3H8 b) C2H6 c) C2H4 d) C2H5OH e) CH4

7. A compound that exhibits resonance is:

a) SO2 b) N2 c) CO2 d) HCl e) NH3

8. The best example of a non-polar molecule containing polar bonds is

a) F2 b) SO2 c) CO2 d) PCl3

9. Which of the following is non-polar molecule?

a) F2O b) PCl3 c) SO2 d) NO21+ e) NO21-

10. Which of the following compound has an expanded octet?

a) H2O b) PH3 c) PCl3 d) PCl5 e) SO3

11. Which contains the shortest oxygen-oxygen bond?

a) O2 b) O3 c) O2 2- d) HO2 1-

12. Which of the following molecules has the shortest bond length?

a) N2 b) O2 c) Cl2 d) Br2 e) l2

13. Which of the following has zero dipole moment (i.e. is non-polar molecule)?

a) H2O b) NO21- c) CCl4 d) SO3 2- e) HF

14. Ionic bonds are the electrostatic attraction between oppositely charged atom. What determines their ionic strength? Explain

1) SIZE (distance) of the atom ↑ size (distance) α ↓electrostatic force

2) Magnitude (amount) - PRODUCT of the charges involved

15. Arrange the following types of attractions in order of increasing strength: Covalent, Electrostatic, Ionic, Dipole-dipole, Hydrogen and London Dispersion forces.

IONIC ( COVALENT

Electrostatic ( Hydrogen Bonding ( Dipole-Dipole ( London Dispersion

(Ion-Ion) w/ FON POLAR NONPOLAR

16. What is the difference between intramolecular and intermolecular bonding?

INTRAmolecular force: holds atoms together in an ionic, covalent or metallic bond.

INTERmolecular force: force is BETWEEN molecules or formula units.

17. Identify the types of intermolecular forces for the following chemical compounds

(HINT: Dipole-Dipole, Electrostatic, Hydrogen or London Dispersion)

NaCl : ____ELECTROSTATIC CO2: ___L.D. _____________________

H2CO : __L.D. \ DIPOLE-DIPOLE NH3: _L.D. \ DIPOLE-DIPOLE \ _HYDROGEN

18. True or False

___T___ a) Water is a polar molecule

___F____ b) Pyramidal molecules have two unshared electron pairs on the central atom.

ONE LONE PAIR

___F___ c) A molecule cannot be non-polar if it contains only polar bonds.

___T___ d) A molecule consisting of 2 atoms is always linear.

___T__ e) Polar molecules have stronger attractions for each other than non-polar molecules have.

19. Describe the TWO factors that determine whether a molecule is polar or non-polar.

1) SYMMETRY

2) ELECTRONEGATIVITY DIFFERENCE

20. Define electronegativity. How does it relate to the intermolecular force between molecules?

Electronegativity – is a relative scale used to determine an element ability to grab electrons.

↑ ΔEN α ↑ intermolecular force (dipole - dipole force)

21. Explain why Chlorine (Cl2) is a gas, bromine (Br2) is a liquid, and iodine (I2) is a solid. Be very specific!

Intermolecular force (IMF) is responsible for the different states of the halogens.

Chlorine, Bromine & lodine are all NONPOLAR MOLECULES which implies

their only intermolecular force is LONDON DISPERSION FORCE.

↑ Atomic size α ↑ London Dispersion Force

22. Rank the following substance from strongest to weakest intermolecular force:

He NH3 NF3 NaCl

__NaCl_ > __ NH3___ > __ NF3___ > __ He ___

Electrostatic Hydrogen Dipole London Dispersion

23. Rank the following substances from strongest to weakest intermolecular force:

HF F2 FCl

____HF____ > ___FCl___ > ____F2_____

Hydrogen Dipole London Dispersion

24. CENTRAL ATOMS – Most of the time SINGLE atoms become the central atom. However if you are required to determine the central atom, it must meet the best two out of three requirements:

1) Atom with the largest number of valence electrons

2) Atom with the largest atomic radius

3) Least electronegative atom

**Note: _Hydrogen___ and __Halogens____ can not be central atoms.

25. Explain why nonpolar molecules usually have much lower surface tension than polar ones.

Nonpolar molecules have NO attraction for each other, therefore

they have a significantly lower surface tension (invisible skin) than polar molecules.

26. Rank the molecules from lowest to highest polarity.

PH3 PF3 NH3 NF3

___PH3____ < __ NH3 ____ < __ NF3____ < ___ PF3 _____

ΔEN = 0 ΔEN = 0.9 ΔEN = 1.0 ΔEN = 1.9

27. Which of the following has dispersion forces as its only intermolecular force?

CH4 HCl C6H13NH2 NaCl CH3Cl

28. Rank the following substances from strongest to weakest intermolecular force

Calcium Chloride Potassium Chloride Sodium Chloride

__CaCl2_____ > ___KCl____ > ___NaCl____

29. CH3CH2CH3 (propane) or CH3CH2CH2CH3 (butane) has the highest melting point

because they both have the same IMF (London Dispersion)

however butane has the higher molecular weight.

30. Draw the lewis structure, identify the shape, state whether it is polar or nonpolar and identify the one with lowest boiling point?

|PH3 |H2S |HCl |SiH4 |

| | | |Lowest Boiling Point |

| | |ΔEN = 2.1 – 3.0 = 0.9 | |

| | | |SHAPE: |

|SHAPE: |SHAPE: |SHAPE: |Tetrahedral |

|Trigonal Pyramidial |Bent |Linear | |

| | | |NONPOLAR or POLAR |

|NONPOLAR or POLAR |NONPOLAR or POLAR |NONPOLAR or POLAR | |

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Chemical Bonding

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