Exam 3 Review

Question 1

Lattice Energy

Answer 1

Energy released when gas-phase ions are converted into solid ionic compound, in kJ/mol

ex. K+(g) + Cl-(g) —> KCl (s), Delta H sub L = -717 kJ/mol

Question 2

Periodic Trend in Lattice Energy

Answer 2

Decreases moving down groups, larger ionic radii have weaker attractions between larger ions as the distance between their nuclei increase, but larger for ionic compounds with large charged ions

Question 3

Valence Bond Theory (3 prongs)

Answer 3

Covalent bonds form from overlaps in valence electrons of atoms involved; 1) # hybrid orbitals created = # atomic orbitals combined, 2) shapes/energies of hybrid orbitals determined by shapes/energies of atomic orbitals being combined, 3) several type of hybrid orbitals possible: type formed for specific molecule is one that results in molecule with lowest possible energy (pi bonds easier to break than sigma bonds, less extensive overlap)

Question 4

Hybrid Orbitals

Answer 4

Mathematical combinations of atomic orbitals resulting in maximal overlap of orbitals in bonds, most likely on central atoms

Question 5

Sigma Bond

Answer 5

Head to head overlap of of any type of orbitals if overlap occurs along internuclear axis (wherever they connect basically)

Question 6

Pi Bond

Answer 6

Bonds formed between unhybridized p orbitals getting too close to each other, overlaps with sigma bond

Question 7

sp3 Hybridization

Answer 7

2s2 + 2p2 -(hybridize)-> 4 sp3 hybrid orbitals –> tetrahedral

Question 8

sp2 Hybridization

Answer 8

2s2 + 2p2 + unhybridized p -(hybridize)-> 3 sp2 hybrid orbitals + unhybridized p –> trigonal planar

Question 9

sp Hybridization

Answer 9

(2s2 + 2p2) + 2 unhybridized p orbitals -(hybridize)-> 2 sp hybrid orbitals + 2 unhybridized p orbitals –> linear

Question 10

Sigma and Pi Bonds Related to Single, Double, Triple Bonds

Answer 10

Single = 1 sigma
Double = 1 sigma + 1 pi
Triple = 1 sigma + 2 pi
… idk lol