(Cc) Chapter 3: Bonding And Chemical Interactions

Front 1

Interesting fact about chlorine and sodium.

Back 1

Pure sodium will produce fire when exposed to water and pure chlorine is toxic that it was used in chemical warfare. But the two of them together will make table salt. Shows how radically chemical bonding can change the properties of an element.

Front 2

Primary motivating factor in atomic bonding

Back 2

Octet rule. Atoms will bond to achieve a greater stabilization through the octet configuration. In essence, atoms will come together so that they will lower their energy

Front 3

Exceptions to the octet rule (3)

Back 3

1) Hydrogen. Not enough space for octet
2) Lithium, Beryllium, and Boron. No real reason why they do not obey rule
3) All elements in period three and above will not obey rule since they have the capacity to hold more than 8 electrons.

Front 4

Two types of covalent bonds

Back 4

Polar and non polar covalent bonds. Polar means that the electrons spend more time in the region around the more electronegative atom than the other atom.

Front 5

Coordinate Covalent

Back 5

This is a type of bond in which the two electrons of the bond were given by a single atom as opposed to each atom giving up one electron

Front 6

What is the force that hold the cation and anion of ionic compounds together?

Back 6

Electrostatic force. The positive and negative force of the two atoms pull them together

Front 7

What must the difference be in electronegativity for a bond to be an ionic bond?

Back 7

The difference must be greater that 1.7.

Front 8

Melting and boiling point of ionic compound

Back 8

Ionic compounds have high melting and boiling points

Front 9

Physical structure of ionic compounds

Back 9

Ionic compounds form crystalline lattice structures

Front 10

Electrical conduction of ionic compounds

Back 10

Ionic compounds a very good conductors of electricity

Front 11

What type of solutions will dissolve ionic compounds and why?

Back 11

Polar solutions will dissolve ionic compounds since the polar end of the molecules of the solution will surround the positive and negative charges of the ionic compound.

Front 12

What keeps the atoms of a covalent bond together?

Back 12

The electrons that are shared are attracted to the positive nuclei of the other atom.

Front 13

Bond Order

Back 13

The total number of shared paired of electrons. A single bond will have a bond order of one, a double bond will have a bond order to two, ect

Front 14

Bond length and number of bonds

Back 14

The more bonds that are present the shorter the bond length

Front 15

Bond Energy

Back 15

The energy needed to break a bond in gas state. The more bonds that are present, the greater the bond energy

Front 16

Non polar covalent bond

Back 16

A bond in which the two atoms of the molecule share electrons equally. This usually happens in diatomic molecules in which the electronegativity is more the less the same.

Front 17

Polar covalent bond

Back 17

In a polar covalent bond, the electronegativity difference between the atoms is greater than .4 but less than 1.7. In this type of bond, the electrons spend more time in one region of the molecule (the region of the more electronegative atom) than other regions. This concentration of electrons around one end of the molecule creates A DIPOLE in which there is a region of positive and negative charge around the molecule.

Front 18

What is the electronegativity difference between atoms that have a polar covalent bond?

Back 18

The difference is greater than .4 but less than 1.7.

Front 19

What is the difference between how chemists and physicists designate a dipole?

Back 19

Chemists will use an arrow point towards the region of negative charge with a cross at the tail end of the arrow by the positive region. Physicists use the opposite notation.

Front 20

How do you calculate the dipole moment?

Back 20

Dipole moment (u) = (q) x (r), where r is the distance between the positive region and the negative region and q is the magnitude of the charge.

Front 21

Where are coordinate covalent bonds usually found?

Back 21

Coordinate covalent bonds in which one atom gives up two electrons in a covalent bond is usually found in interactions between lewis acids and lewis bases

Front 22

Procedure for writing out lewis structures

Back 22

1) Count up the total number of valence electrons
2) Draw out skeleton
3) Starting adding electrons to atoms that need to fill octet.
4) If atom does not have octet, use other electrons to make double and triple bonds

Front 23

Equation for formal charge

Back 23

Formal Charge = Group Number - {# of non bonding electrons - (1/2 x # of bonding electrons)}

Front 24

What is formal charge used for?

Back 24

Formal charge is used to assess the extent to which a resonance structure represents the actual structure.

Front 25

What is the difference between oxidation number and formal charge?

Back 25

The only difference between the two is that oxidation number overestimates the effect of electronegatvity and and formal charge underestimates the effect of electronegatvity.

Front 26

Resonance Structure

Back 26

When writing out resonance structures, think of the double bonds as concentration of electrons that can move and lone pairs as concentrations of electrons that can move.

Front 27

Formal Charge and Lewis Structure

Back 27

1) No formal charge is preferred over a structure with a charge
2) Less separation between charges is preferred over more separation on the lewis structure
3) A lewis structure where the negative charge is placed on the more electronegative atom is preferable.

Front 28

Valence Shell Electron Pair Repulsion Theory

Back 28

States that the three dimensional arrangement of atoms surrounding a central atom in determined by the repulsions between the bonding and non bonding electron pairs in the valence shell of the central atom.

Front 29

VSEPR Example BeCl2

Back 29

Linear. 180

Front 30

VSEPR Example BH3

Back 30

Trigonal Planar. 120

Front 31

VSEPR Example CH4

Back 31

Tetrahedral. 109.5

Front 32

VSEPR Example PCl5

Back 32

Trigonal Bipyramidal. 90, 120, 180.

Front 33

VSEPR Example SF6

Back 33

Octahedral. 90, 180.

Front 34

What is the difference between the electron geometry and the molecular geometry?

Back 34

The electron geometry takes into consideration the three dimensional configuration of the bonding electrons and the non bonding electrons. The molecular geometry deals only with three dimensional configuration of the molecules themselves.

Front 35

How do lone pair affect the geometry of the molecule?

Back 35

The presence of a lone pair on a molecule will act as a force on the molecule which will cause a deviation from the ideal bond angles

Front 36

Does a molecule that has polar bonds need to be polar?

Back 36

No. The fact that a molecule has polar bonds does not mean that it is polar. A molecule with polar bonds can have bonds that are pointing in directions in which the bonds will cancel eachother out. In CCl4, each of the bonds are polar but the molecule is not polar because each of the bonds is canceled out.

Front 37

What quantum number will give you s, p, d, f?

Back 37

The azimuthal quantum number (l)

Front 38

London Dispersion Forces

Back 38

These forces are created between molecules in which there is a temporary dipole created. This occurs because as the electrons are moving around the molecule, for a moment they may concentrate in a specific region creating a dipole. These dipole will attract other dipoles creating an attraction between the molecules.

Front 39

What is the difference between london forces and dipole interactions?

Back 39

The only difference between the two is simply a matter of degree.

Front 40

How does the size of the molecule affect the strength of the london force?

Back 40

The larger the size the of the molecule the large the size of the electron cloud. If the molecule has a larger electron cloud then the electrons have a greater tendency to concentrate at one point of the molecule. This means that the greater the size of the molecule, the greater the london force.

Front 41

What are the common atoms that can hydrogen bond?

Back 41

O, N, and F

Front 42

What is hydrogen bonding?

Back 42

Another version of a dipole in which the hydrogen takes on a positive charge and the oxygen (or F/N) takes on a negative charge. This difference in charge will create an attraction between the two parts of the molecule.

Front 43

Unique property of hydrogen bonds

Back 43

One unique feature of hydrogen bonds is that molecules that exhibit hydrogen bonding will have unusually high boiling points. One example is the difference between a carboxylic acid and an acyl halide. The acyl halide has a halogen in the region where the carboxylic acid could hydrogen bond. For this reason the boiling point for carboxylic acid is higher than it is for an acyl halide.