CHEM 101 Winter 2026 Exam 2 (A,B & C) Complete Questions
and Answers.
CHEM 101 Winter 2026 Exam 2 (A)
On the answer sheet (scantron) write your last name, first name initial (FI), middle name initial
(MI) (if applicable), Drexel ID number, and lab section number. Choose the best (most correct)
answer for each question and fill in the corresponding bubbles for all 26 questions. Look at the
example of a correctly filled bubble at the top of your scantron sheet. Do NOT go past the frame
of the bubbles. DO NOT CROSS OUT bubbles. DO NOT MARK/WRITE anything else on the
scantron sheet.
Note: a copy of the periodic table has been provided at the end page of this exam.
Potentially useful data:
Avogadro’s constant: 6.02 × 1023 mol-1
speed of light: c = 3.00 × 108 m/s
c=νλ
Ephoton = hν
1 Hz = 1 s-1
Planck’s constant: h = 6.63 × 10-34 J∙s
Rydberg constant: RH = 2.179 × 10-18 J
ΔE = – RH (1/nf2 – 1/ni2)
Questions:
1.Please choose the letter “A” as your answer for this question.
2. Of the choices below, which one is not an ionic compound?
A) MgCl2 B) PCl5 C) NaCl D) FeCl2 E) RbCl
Answer: B
3. In which set of elements would all members be expected to have very similar chemical
properties?
A) S, Se, Si
B) Na, Mg, K
C) N, O, F
D) Ne, Na, Mg
E) O, S, Se
Answer: E
,4. Calculate the percentage by mass of lead in Pb(NO3)2.
A) 38.6% B) 71.2% C) 65.3% D) 62.6% E) 44.5%
Answer: D
5. How many orbitals are contained in the third principal level (n = 3) of a given atom?
A) 9
B) 3
C) 18
D) 7
E) 5
Answer: A
6. For a hydrogen atom, calculate the wavelength of an emitted photon in the Lyman series that
results from the transition n = 3 to n = 1.
A) 102.6 nm
B) 95.0 nm
C) 91.2 nm
D) 434.1 nm
E) 1005 nm
Answer: A
7. Which of the following elements is NOT a metal?
A) Ba
B) Mg
C) Xe
D) Pb
E) Ga
Answer: C
8. The element that corresponds to the electron configuration 1s22s22p63s23p64s13d5 is
A) titanium (Ti)
B) vanadium (V)
C) chromium (Cr)
D) manganese (Mn)
E) iron (Fe)
Answer: C
9. Give the number of valence electrons for XeI2.
A) 22
B) 20
, C) 18
D) 24
E) 16
Answer: A
10. Which electron configuration represents a violation of the Pauli exclusion principle?
A)
B)
C)
D)
E)
Answer: B
11. Of the choices below, which gives the order for first ionization energies?
A) Cl > S > Al > Si > Ar
B) Al > Si > S > Cl > Ar
C) Cl > S > Al > Ar > Si
D) Ar > Cl > S > Si > Al
E) S > Si > Cl > Al > Ar
and Answers.
CHEM 101 Winter 2026 Exam 2 (A)
On the answer sheet (scantron) write your last name, first name initial (FI), middle name initial
(MI) (if applicable), Drexel ID number, and lab section number. Choose the best (most correct)
answer for each question and fill in the corresponding bubbles for all 26 questions. Look at the
example of a correctly filled bubble at the top of your scantron sheet. Do NOT go past the frame
of the bubbles. DO NOT CROSS OUT bubbles. DO NOT MARK/WRITE anything else on the
scantron sheet.
Note: a copy of the periodic table has been provided at the end page of this exam.
Potentially useful data:
Avogadro’s constant: 6.02 × 1023 mol-1
speed of light: c = 3.00 × 108 m/s
c=νλ
Ephoton = hν
1 Hz = 1 s-1
Planck’s constant: h = 6.63 × 10-34 J∙s
Rydberg constant: RH = 2.179 × 10-18 J
ΔE = – RH (1/nf2 – 1/ni2)
Questions:
1.Please choose the letter “A” as your answer for this question.
2. Of the choices below, which one is not an ionic compound?
A) MgCl2 B) PCl5 C) NaCl D) FeCl2 E) RbCl
Answer: B
3. In which set of elements would all members be expected to have very similar chemical
properties?
A) S, Se, Si
B) Na, Mg, K
C) N, O, F
D) Ne, Na, Mg
E) O, S, Se
Answer: E
,4. Calculate the percentage by mass of lead in Pb(NO3)2.
A) 38.6% B) 71.2% C) 65.3% D) 62.6% E) 44.5%
Answer: D
5. How many orbitals are contained in the third principal level (n = 3) of a given atom?
A) 9
B) 3
C) 18
D) 7
E) 5
Answer: A
6. For a hydrogen atom, calculate the wavelength of an emitted photon in the Lyman series that
results from the transition n = 3 to n = 1.
A) 102.6 nm
B) 95.0 nm
C) 91.2 nm
D) 434.1 nm
E) 1005 nm
Answer: A
7. Which of the following elements is NOT a metal?
A) Ba
B) Mg
C) Xe
D) Pb
E) Ga
Answer: C
8. The element that corresponds to the electron configuration 1s22s22p63s23p64s13d5 is
A) titanium (Ti)
B) vanadium (V)
C) chromium (Cr)
D) manganese (Mn)
E) iron (Fe)
Answer: C
9. Give the number of valence electrons for XeI2.
A) 22
B) 20
, C) 18
D) 24
E) 16
Answer: A
10. Which electron configuration represents a violation of the Pauli exclusion principle?
A)
B)
C)
D)
E)
Answer: B
11. Of the choices below, which gives the order for first ionization energies?
A) Cl > S > Al > Si > Ar
B) Al > Si > S > Cl > Ar
C) Cl > S > Al > Ar > Si
D) Ar > Cl > S > Si > Al
E) S > Si > Cl > Al > Ar
