Molecular bonds and interactions

Question 1

VESPR theory

Answer 1

Core principle: valence electrons repel each other and form into a geometry that maximizes the distance between them.

Electronic geometry = “default” geometry for that hybridization when no lone pairs exist

Question 2

VESPR

Hybridization, electron geometry, and molecular geometry of 2 electron groups

Answer 2

sp
Linear
Linear

Question 3

VESPR

Hybridization, electron geometry, and molecular geometry of 3 electron groups

Answer 3

sp2

Trigonal planar

0 lone pair: Trigonal planar
1 lone pair: Bent

Question 4

VESPR

Hybridization, electron geometry, and molecular geometry of 4 electron groups

Answer 4

sp3

Tetrahedral

0 lone pair: Tetrahedral
1 lone pair: Trigonal pyramid
2 lone pairs: Bent

Question 5

VESPR

Hybridization, electron geometry, and molecular geometry of 5 electron groups

Answer 5

sp3d

Trigonal bipyramidal

0 lone pair: Trigonal bipyramidal
1 lone pair: Seesaw
2 lone pairs: T-shaped
3 lone pairs: Linear

Question 6

VESPR

Hybridization, electron geometry, and molecular geometry of 6 electron groups

Answer 6

sp3d2

Octahedral

0 lone pair: Octahedral
1 lone pair: Square pyramidal
2 lone pairs: Square planar
3 lone pairs: T-shaped
4 lone pairs: Linear

Question 7

Intermolecular forces
Order of strength:

Answer 7

hydrogen > dipole-dipole > London dispersion.

Question 8

Intermolecular forces

Hydrogen bonds

Answer 8

Formed between an acceptor with a lone e- pair, and an electronegative donor with hydrogen (three most common are FH, NH, and OH).

Question 9

Intermolecular forces

Dipole-dipole

Answer 9

Attraction between charged ends of polar molecules (ie HCl). Force is dependent on difference in polarity.

Question 10

Intermolecular forces

London dispersion

Answer 10

Attraction due to motion of electrons, existing between all molecules.

Question 11

Intermolecular forces

Van der waals forces

Answer 11

Umbrella term that describes dipole-dipole and London dispersion forces.

Question 12

Bonds

Covalent bond

Answer 12

Bond formed by electrons between atoms of close electronegativity.
Single covalent bond = sigma bond (σ). Double covalent bond = 1 sigma bond (σ) and 1 pi bond (π).

Question 13

Bonds

Bond order

Answer 13

Bond order refers to the number of covalent bonds (ie single, double). Increasing bond order means increased bond strength and energy and decreased bond length.

Question 14

Bonds

Coordinate covalent bond

Answer 14

Covalent bond formed when one atom provides both bonding electrons. Generally formed by Lewis acid-base interactions.

Question 15

Bonds

Types of bonds

Answer 15

Defined by difference in electronegativity between the two atoms.
< 0.5 = nonpolar, 0.5-1.7 = polar, > 1.7 = ionic

Question 16

Bonds

Ionic bonds

Answer 16

Formed by full transfer of valence e-. Interaction between one atom with high electron affinity and another with low ionization energy.