Chapter 6 Chemical Bonding

Draw Lewis strictures to represent the following: C2H2

C2H2

Give formula, Lewis structure, geometry, and if they are Polar or Not polar: CCl4

CCl4- Tetrahedral; Not Polar

Draw Lewis strictures to represent the following: CH2O

CH2O

What are the components of one formula unit of CaF2?

Ca: + ::F:. + ::F:. --> Ca2+ + ::F::- + ::F::-

Draw Lewis strictures to represent the following: CH4

Ch4

What is metallic bonding?

The chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons is called metallic bonding.

Bonds that posses between 5% and 50% ionic character are considered to be _______.

non polar covalent

A chemical bond between atoms results from the attraction between electrons and _____.

protons

Give two examples of polyatomic ions.

(NH4)+ and (SO4)2-

In metals, the valence electrons are considered to be ________.

shared by all surrounding atoms.

The electrons involved in the formation of a chemical bond are called ___________.

valence electrons

Identify and define the three major types of chemical bonding.

Chemical bonding that results from the electrical attraction between large numbers of cations and anions is called ionic bonding. Covalent bonding results from the sharing of electron pairs between two atoms. The chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons is called metallic bonding.

Describe the octet rule in terms of noble-gas configurations and potential energy.

Chemical compounds tend to form so that each atom, by gaining, losing, or sharing electrons, has an octet of electrons in its highest occupied energy level.

In what form do most ionic compounds occur?

Crystalline solids.

In what form do polyatomic ions often occur in nature?

Crystalline solids.

What accounts for the observed differences in the properties of ionic and molecular compounds?

Depending on the differences of the two's properties, the properties can tell people how strong a bond is and what the bond is.

What are dipole-dipole forces?

Dipole-dipole forces are intermolecular forces of attraction between two polar molecules.

Study The Notes. Mr. Pope said it's the best thing to do.

Good Luck!

Determine the number of valence electrons in an atom of each of the following elements: H, F, Mg, O, Al, N, C

H - 1 F - 7 Mg - 2 O - 6 Al - 3 N - 5 C - 6

Bond Energy is related to bond length. Use the data below to arrange the bonds listen in order of increasing bond length, from shortest bond to longest. Bond Bond Energy H-F 569 H-I 299 H-Cl 432 H-Br 366

H-F, H-Cl, H-Br, H-I

Draw Lewis strictures to represent the following: H20

H20

Give formula, Lewis structure, geometry, and if they are Polar or Non-polar: H2O

H20-Bent; Polar

Give formula, Lewis structure, geometry, and if they are Polar or Non-polar: H2S

H2S- Bent; Polar

What are hybrid orbitals?

Hybrid orbitals are orbitals of equal energy produced by the combination of two or more orbitals on the same atoms.

What is hydrogen bonding?

Hydrogen bonding is the intermolecular force in which a hydrogen atom is bonded to a highly electronegative atom and is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule.

Name two elements that form compounds that are exceptions to the octet rule.

Hydrogen, Boron, Beryllium, Phosphorus, Sulfur, and Xenon

Diatomic Molecules

Hydrogen, Nitrogen(3 bonds) Fluorine, Carbon, Bromine, Iodine Henry's Nose Flows Clear Brown Ink

How are dipole-dipole attractions, London dispersion forces, and hydrogen bonding similar?

In all cases there is an attraction between the slightly negative portion of one molecule and the slightly positive portion of another molecule.

What are IMF's?

Intermolecular Forces

What are intermolecular forces?

Intermolecular forces are forces of attraction between molecules.

In general, how do ionic and molecular compounds compare in terms of melting points, boiling points, and ease of vaporization?

Ionic compounds tend to have a higher melting point, and boiling point. Ionic compounds at room temperature tend not to vaporize. Molecular compounds have low melting and boiling points, and vaporize at room temperature.

What is the everyday importance of this type of intermolecular force?

It results in an attraction to make the water molecule.

The lattice energy of compound A is greater than that of compound B. What can be concluded from this fact?

It will be more difficult to break the bonds in compound A than in compound B.

Arrange the ionic bonds below in order of increasing strength from weakest bond to strongest: Ionic Bond Lattice Energy NaCl -787 CaO -3384 KCl -715 MgO -3760 LiCl -861

KCl, NaCl, LiCl, CaO, MgO

What is lattice energy?

Lattice energy is the energy released when one mole of an ionic crystalline compound is formed from gaseous ions.

What are London dispersion forces?

London dispersion forces are the intermolecular attractions resulting from the constant motions of electrons and the creation of instantaneous dipoles.

Give formula, Lewis structure, geometry, and if they are Polar or Non-polar: PCl5

PCL5- Trigonal Bypyramidal; Not Polar

Where are the strongest intermolecular forces found?

Polar molecules.

Distinguish between polar-covalent and nonpolar-covalent bonds.

Polar-covalent bond is a covalent bond in which the bonded atoms have an unequal attraction for the shared electrons. Non-polar covalent is when the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge.

Give formula, Lewis structure, geometry, and if they are Polar or Non-polar: SF6

SF6- Octahedral; Not Polar

Draw lewis structures for the following polyatomic ion: SO4 2-

SO4 2-

Describe the role of each of the following in predicting molecular geometries: A. Unshared electron pairs B. Double bonds

A. Unshared electron pairs- they change the shape of the molecule, usually in a way that pushes them away (ex. H2O molecule). B. Double bonds- they are treated the same way as single bonds.

According to the VSEPR theory, what molecular geometries are associated with the following types of molecules?

AB2 - linear AB3 - trigonal-planar AB4 - tetrahedral AB5 - trigonal-bypyramid AB6 - octahedral

From memory, write the shape for the following VSEPR notations?

AB2E- bent AB2E2- bent AB4- tetrahedral AB2- liner AB6- octahedral AB3- trigonal planar

What is an ionic compound?

An ionic compound is composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal.

As applied to covalent bonding, what is meant by an unshared or lone pair of electrons?

An unshared or lone pair is what is not involved in a bond. These are above atoms that are bonded with others atoms, but still have left over or "unshared" electrons.

In general, what is the relationship between lattice energy and the strength of ionic bonding?

As an ionic bond's strength increases, the lattice energy increases as well.

Give formula, Lewis structure, geometry, and if they are Polar or Non-polar: BF3

BF3- Trigonal Planar; Not Polar

Give formula, Lewis structure, geometry, and if they are Polar or Non-polar: BeF2

BeF2- Linear; Not Polar

Distinguish between single, double, and triple covalent bonds by defining each and providing an illustration of each type.

A single bond is a covalent bond produced by the baring of one pair of electrons between two atoms ex) - . A double is a covalent bond produced by the sharing of two pairs of electrons between two atoms ex) = . A triple bond is a covalent bond produced by the sharing of three pairs of electrons between two atoms ex) = .

In writing Lewis structures, how is the need for multiple bonds generally determined?

By drawing lines between atoms to shows bonds when the octet rule isn't reached.

How can the strength of metallic bonding be measured?

By the heat of vaporization.

Bond Energy is related to bond length. Use the data below to arrange the bonds listen in order of increasing bond length, from shortest bond to longest. Bond Bond Energy C-C 346 C(triple)C 835 C=C 612

C(triple)C, C=C, C-C

What is the relationship between the vaporization of a metals and the strength of the bonds that hold the metal together?

The amount of heat required to vaporize a metal of the strength of the bonds that hold the metal together.

When drawing Lewis structures, which atom is usually the central atom?

The atom that is usually the central atom is whichever one has a smaller electronegativity. This also means that if you have CaF2 the central atoms will be Ca because it has one Ca, while F has 2.

What type of bonding holds together a polyatomic ion together?

The atoms in a polyatomic ion are held together with covalent bonds, but polyatomic ions combine with ions or opposite charge to form ionic compounds.

What accounts for its extraordinary strength?

The difference in their charges.

What is the relationship between electronegativity and the polarity of a chemical bond?

The differences in electronegativity of atoms involved in a bond that cause it to be polar.

What determines bond length?

The distance between two atoms at their minimum potential energy that is the average distance between two atoms

In water, two hydrogen atoms are bonded to one oxygen atom. Why isn't water a linear molecule?

The electron pairs that are not involved in bonding also take up space, creating a tetrahedral of electron pairs.

Describe the force that holds two atoms together in an ionic bond.

The force of attraction between unlike charges heads a negative ion and a positive ion together in an ionic bond.

How does the behavior of electrons in metals contribute to the metal's ability to conduct electricity and heat?

The mobility of electrons in a network of metals atoms contributes to the metal's ability to conduct electricity and heat.

What determines the number of hybrid orbitals produced by an atom?

The number of hybrid orbitals produced equals the number of orbitals that have been combined.

What orbitals combine together to form sp3 hybrid orbitals around a carbon atom?

The s orbital and all three p orbitals from the second energy level.

What is the meaning of the term polar, as applied to chemical bonding?

The term polar means that they have an uneven distribution of charge.

What determines the polarity of a molecule?

The thing that determines the polarity of a molecule is the difference in its electronegativity between the atoms in the molecule.

What properties of metals contribute to their tendency to form metallic bonds?

The valence electrons being able to move from one atom to another without a problem.

Describe the general location of the electrons in a covalent bond.

They are in overlapping orbitals (in the middle of two atoms).

How are double and triple bonds represented in VSEPR theory?

They are not represented in VSEPR theory.

In general, how do these forces compare in strength with those in ionic and metallic bonding?

They are weaker than bonds.

What specific property of metals accounts for their unusual electrical conductivity?

They share sea of electrons that are allowed to conduct electricity.

How is the VSEPR theory used to classify molecules?

VSEPR theory says that valence level electrons cause them to be as far away from one another as possible.

In general, what determines whether atoms will form chemical bonds?

What determines whether atoms will form chemical bonds is to maximize the stability.

What is meant by an induced dipole?

Within London Dispersion Forces are induced dipole adjacent to an atom.

A covalent bond consists of ________.

a shared electron pair

Write the formula for an example of the following compounds: a. non polar covalent compound b. polar covalent compound c. ionic compound

a. non polar covalent compound- H2 b. polar covalent compound- HCl c. ionic compound- NaCl

As light strikes the surface of a metal, the electrons in the electron sea ________.

absorb and re-emit the light.

The fact that metals are malleable and ionic crystals are brittle is best explained in terms of their _______.

chemical bonds.

When a metal is drawn into a wire, the metallic bonds ________.

do not break

What property go the two atoms in a covalent bond determines wether or not the bond will be polar?

electronegativity

What two factors determine whether or not a molecule is polar?

electronegativity difference and molecular geometry.

The notation for sodium chloride, NaCl, sands for one ______.

formula unit

Atoms with a strong attraction for electrons they share with another atom exhibit ___________.

high electronegativity

The strength of a metallic bond _______ moving from left to right on any row of the periodic table.

increases.

A chemical bond that results from the electrostatic attraction between positive and negative ions is called an _______.

ionic bond

If a bond;s character is more the 50% ionic, then the bond is called an _____.

ionic bond

The greater the electronegativity difference between two atoms bonded together, the greater the bond's percentage of __________.

ionic character

What type of energy best represents the strength of an ionic bond?

lattice energy

Compared with the neutral atoms involved in the formation of an ionic compound, the crystal lattice the results is _____.

lower in potential energy

Mobile electrons in the metallic bond are responsible for_______.

luster, electrical conductivity, and thermal conductivity.

In a crystal of an ionic compound, each cation is surrounded by a number of ______.

negative ions

If two covalently bonded atoms are identical, the bond is identified as ________.

non polar covalent

Identify the major assumption of the VSEPR theory that is used to predict the shape of atoms.

pairs of electrons repel one another.

A covalent bond in which there is an unequal attraction for the shared electrons is ___________.

polar

If electrons involved in bonding spend most of the time closer to one atom rather than the other, the bond is _________.

polar covalent

The forces of attraction between molecules in a molecular compound are _________.

weaker than the attractive forces in ionic bonding

In general, how are bond energies and bond lengths related?

A bonds length, determines a bonds energy. So she shorter the bond length, the stronger the bond energy. Then longer the bond length the weaker the bond energy.

What is unique about the bonding properties of carbon?

A carbon atom can form 4 covalent bonds. It also bonds with other carbon atom to form long-chain molecules of different sizes and shapes.

What is a chemical bond?

A chemical bond is a mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together.

Cite three physical properties of ionic compounds.

1. They have high melting points 2. They are brittle 3. They are electrical conductors in their molten(liquid) states or when dissolved in water.

A bond's character is more than 50% ionic if the electronegativity difference between the two atoms is greater than ______.

1.7

What is a formula unit?

A formula unit is the simplest collection of atoms for which an ionic compound's formula can be established.

What is a molecule?

A molecule is a neutral group of atoms that are held together by covalent bonds.

Describe how a covalent bond holds two atoms together.

A pair of electrons is attracted to both nuclei of the two atoms bonded together.

What is a polyatomic ion?

A polyatomic ion is a charged group of covalently bonded atoms

Arrange the following types of attractions in order of increasing strength, with 1 being the weakest and 4 the strongest. Covalent Ionic Dipole-Dipole London Dispersion

1. London Dispersion 2. Dipole-Dipole 3. Covalent 4. Ionic

What is the relationship between electronegativity and the ionic character of a chemical bond?

Electronegativity is a measure of an atom's ability to attract electrons, which is needed to find if a chemical bond is ionic. If it is ionic it would have an ionic character of 1.7% or less.

What molecular geometry would be expected for F2 and HF?

F2- linear HF- linear

Complete the following table: Metallic Ionic Components Overall Charge Conductivity Melting Point Hardness Malleable Ductile

Metallic Ionic Components -atoms -ions Overall Charge -neutral -neutral Conductivity -yes -no Melting Point -low to high -high Hardness -soft to hard -hard Malleable -yes -no Ductile -yes -no

How do the properties of metals differ from those of both ionic and molecular compounds?

Metals are shiny, usually solid at room temperature, malleable, ductile, highly conductive. Molecular compounds tend to be gases at room temperature and ionic compounds tend to be brittle making them both different form metallic compounds. Metals are good conductors or heat, many different melting points, ductile, malleable.

Use the concept of electron configurations to explain why the number of valence electrons in metals tends to be less than the number in most nonmetals.

Most metals have their outer electrons in s orbitals, while nonmetals have their outer electrons in p orbitals.

Draw lewis structures for the following polyatomic ion: NH+4

NH+4

Draw Lewis strictures to represent the following: NH3

NH3

Draw the two resonate structures for the nitrate anion, NO2-

NO2-