Chem 341, Quiz #1B 15 points total Your score:______of 13. Date: 8/31
Name (Last, First): _______________KEY__________________P # : _______________
Please, write and draw in legible manner. The answer the grader cannot read/understand will be considered wrong! All questions that are A/B/C/D must be
answered A/B/C/D. If you leave the window for answer empty, it means you did not answer.
Your answer
1.
Draw energy diagram corresponding to nitrogen in the molecule of ammonia. Do not draw electrons that
come from hydrogens (nitrogen electrons only!).
Do not write
here
E
3 sigma bonds
2p-orbital level
_____/2
sp3
2e- of the lone pair
2s-orbital level
2.
Ozone is a rare form of molecular oxygen that has summary formula O3 and non-cyclic structure. Draw a
Lewis structure of ozone, place correct formal charges and draw 1 additional possible/probable canonical
form:
O
O
O
O
_____/2
O
O
Do not write
here
This assignment will not be counted – I forgot I said that there will be no resonance in the quiz, sorry.
3.
What are the correct formal charges on the labeled atoms in the following structure?
A) i, 0; ii, +2; iii, +1
4.
N
i
ii
iii
C
C) i, -1; ii, +1; iii, 0
D) i, -1; ii, +1; iii, +1
Which of the following structures contains an sp2-hybridized nitrogen atom?
H2
H2
C
C
CH3
CH
H3C
H2C
N
H2C
CH3
2
1
H2
C
C
N
C
H2
N
NH4+
OH
4
3
B) sp + sp
C) p +p
C
D) sp2 + sp2
The angle between bonds in CH4 is:
A
A) 109.5o ; B) 109.6 o ; C) 109.0 o ; D) 120.0 o
7.
9.
Do not write
here
Place correct formal charges above the appropriate atoms:
H
8.
D
A) 3; B) 4; C) 1; D) 2
Which atomic orbitals of carbon overlap to form the two carbon-carbon π bonds of acetylene, HC≡CH?
A) sp3 + sp3
6.
N
B) i, -2; ii, +2; iii, 0
H3C
5.
H 2C
N
N
N
H
N
N
N
Which of the following statements is not true regarding valence bond theory?
A) The pair of electrons in a bond is shared by the two atoms.
B) Stronger bonds are formed when there is a larger degree of overlap between atomic orbitals.
C) Covalent bonds are formed by overlap of two atomic orbitals, each containing one electron.
D) The spins of the two electrons in a bond possess identical spin.
Which of the following elements has the highest electronegativity?
A) H ; B) S ; C) C ; D) Cl
CHEM341 Quiz #1, page 1
_____/2
D
D
10.
11.
12.
Which atomic orbitals overlap to form the carbon-carbon σ bond and π bond of ethylene, H2C=CH2?
A) σ: sp3 + sp3, and π: sp2 + sp2
B) σ: sp2+ sp2, and π: p + p
C) σ: sp3 + sp3, and π: p + p
D) σ: sp2 + sp2, and π: sp2 + sp2
Which of the statements is not true about electronegativity (EN) of elements in the periodic system (PS)?
A) The fluorine has the highest electronegativity value in the periodic system.
B) The EN values generally increase from bottom rows toward top rows in the PS.
C) All the elements in the first column of PS have the lowest EN values, in fact, they are considered to be
electropositive.
D) The elements on the right side of PS have generally higher EN values compared to the elements on the
left side.
B
C
Which of the following structures has the wrong assignment of hybridization of the atoms?
C
A) 1; B) 4; C) 3; D) 2
CHEM341 Quiz #1, page 2