FINAL EXAM- VESPR

Question 1

Electronegativity

Answer 1

measure of the ability of an atom in a compound to attract electrons from another atom in a compound. The attraction an atom has for a pair of electrons in a bond.

Question 2

Polar covalent bond

Answer 2

A covalent bond in which a pair of electrons shared by two atoms is held more closely by one atom. Unequal sharing.

Question 3

Nonpolar covalent bond

Answer 3

A covalent bond in which the bonding electrons are equally attracted to both bonded atoms. Perfect sharing, same attraction.

Question 4

Dipole

Answer 4

A molecule or part of a molecule that contains both positively and negatively charged regions. “little bit”

Question 5

Linear

Answer 5

A molecule whose atoms are arranged so that the bond angle between each is 180 degrees.

Question 6

Angular

Answer 6

aka bent, a molecule whose atoms are arranged so that the bond angle between each is 105 degrees.

Question 7

Trigonal planar

Answer 7

A molecule whose atoms are arranged so that the bond angle between each is 120 degrees.

Question 8

Trigonal pyramidal

Answer 8

A molecule whose atoms are arranged so that the bond angle between each is 107 degrees.

Question 9

tetrahedral

Answer 9

A molecule whose atoms are arranged so that the bond angle between each is 109.5 degrees.

Question 10

Polar molecule

Answer 10

molecules with uneven geometric distribution of dipoles.

Question 11

Nonpolar molecule

Answer 11

Even geometric distribution of dipoles or no dipoles.

Question 12

Van der Waal forces

Answer 12

AKA London dispersion forces. The attraction of intermolecular forces between molecules.

Question 13

Dipole-Dipole attraction

Answer 13

attraction between polar molecules. Each molecule has polar bond and based on shape, bond doesn’t cancel geometrically.

Question 14

London Dispersion forces

Answer 14

All molecules display this type of IMF, but it is the only IMP in nonpolar molecules.

Question 15

Hydrogen bonds

Answer 15

The intermolecular force occurring when a hydrogen atom that is bonded to a highly electronegative atom of one molecule is attracted to two unshared electrons of another molecule. Type of Dipole-Dipole attraction, very strong, the strongest IMF, only occurs in molecules that have hydrogen bonded to a highly electronegative atom (O, F, Cl, and N)

Question 16

Intermolecular forces

Answer 16

forces between molecules.

Question 17

Intramolecular forces

Answer 17

any force that holds together the atoms making up a molecule or compound. Aka covalent and ionic bonds.

Question 18

Bond strength

Answer 18

The strength with which a chemical bond holds two atoms together

Question 19

Bond length

Answer 19

The average distance between nuclei of two bonded atoms in a molecule.

Question 20

Given electronegativities be able to determine bond type.

Answer 20

• Take the two given electonegativities and subtract the smaller one from the bigger one.
• If the difference is 0-0.4, it is nonpolar covalent
• If the difference is greater than 0.4 and less than or equal to 1.9 it is polar covalent
• If the difference is above 1.9 it is ionic

Question 21

Determine bond type from the relative position of the elements on the periodic table

Answer 21

• If the two elements are very far away from each other, they are ionic
• If the two elements are close together, they are covalent.
• Kind of close=polar covalent
• Really close=nonpolar covalent

Question 22

Know how to draw Lewis dot diagrams and exceptions

Answer 22

• Write each individual element symbol and the number of them in the compound (subscript)
• Put the least electronegative one (usually the ones there’s less of) in the middle and even space the symbols of the other element around it.
• Draw the number of valence electrons the element has around each symbol representing them with dots or x’s.
• Draw circles so that each element has 8 valence electrons
• The only exceptions to the 8 valence electrons is that H has 2, B has 6, and Be has 4.

Question 23

Know how to draw a line structure

Answer 23

• Arrange the symbols in the same way you would if you were drawing a lewis dot diagram
• Instread of using dots, represent pairs of electrons with lines, including bonded pairs

Question 24

Be able to determine one of 5 molecular shapes

Answer 24

• Choices are Linear, trigonal pyramidal, tetrahedral, trigonal pyramidal, and angular/bent
• You can determine which one it is by counting the number of lone pairs vs bonded pairs.

Question 25

Lone pairs

Answer 25

the pairs of electron around the center atom that are not bonded and bonded pairs are the pairs of electrons between two elements.

Question 26

lone/bonded for the shapes

Answer 26

• 0/2=linear
• 0/3= trigonal planar
• 0/4=tetrahedral
• 1/3=trigonal pyramidal
• 2/2=angular/bent

Question 27

Be able to determine whether a molecule is polar or nonpolar

Answer 27

• First determine if the bonds are polar or nonpolar by subtracting the electronegativities
• If it has polar covalent bonds, it has dipoles
• If there are nonpolar covalent bonds, there are no dipoles
• If there are no dipoles, its automatically nonpolar
• Next you have to look at the shape
• If the angles are even and cancel out, its nonpolar
• If the angles are uneven and don’t cancel out, its polar
• Think of dogs on leashes
• More often its nonpolar I

Question 28

Be able to determine the intermolecular force displayed between molecules

Answer 28

• Choices are Hydrogen bond, Dipole-Dipole, and London Dispersion
• H bond if it contains Hydrogen
• Dipole-Dipole if its molecular polarity is polar
• All have LDF

Question 29

Know the effect of intermolecular forces on dissolving and phase change

Answer 29

• The strength of attractive forces between particles determines a substance’s phase at room temperature
• The stronger the attraction, the harder it is to change phases, and the more solid it will be
• The weaker the attraction, the easier it is to change phases and will be gaseous
• Like dissolves like so for example, D-D will dissolve easily in D-D