CHY 103 Final Exam | Full Questions and
Answers | 2026 Revised Updated | 100%
Correct - Toronto Metropolitan University.
CHY 103 Final Exam | Full Questions and Answers | 2026 Revised Updated |
100% Correct - Toronto Metropolitan University
SECTION 1: Atomic Structure and Periodicity
1. Which of the following subatomic particles has a relative charge of +1 and a
mass of approximately 1 amu?
A) Electron
B) Proton
C) Neutron
D) Positron
Correct Answer: B
Explanation: The proton has a relative charge of +1 and a mass of approximately 1
atomic mass unit (amu). Electrons have a charge of -1 and negligible mass.
Neutrons have no charge and a mass of approximately 1 amu.
2. An atom of carbon-14 has how many neutrons?
A) 6
B) 8
,C) 14
D) 20
Correct Answer: B
Explanation: Carbon-14 has an atomic number of 6 (6 protons) and a mass
number of 14. The number of neutrons is 14 - 6 = 8.
3. Which of the following is the correct electron configuration for a neutral
oxygen atom (atomic number 8)?
A) 1s² 2s² 2p⁴
B) 1s² 2s² 2p⁶
C) 1s² 2s² 2p³
D) 1s² 2s² 2p⁵
Correct Answer: A
Explanation: Oxygen has 8 electrons. The electron configuration is 1s² 2s² 2p⁴.
Option B is neon (10 electrons), Option C is nitrogen (7 electrons), and Option D is
fluorine (9 electrons).
4. A student is studying the rotation of the electron around the nucleus.
According to the Bohr model, electrons:
A) Move in fixed circular orbits around the nucleus
B) Are randomly distributed around the nucleus
C) Exist in a cloud of probability
D) Are stationary
Correct Answer: A
Explanation: The rotation of the electron around the nucleus in the Bohr model
occurs in fixed circular orbits with quantized energy levels. The quantum
mechanical model describes electrons in probability clouds (orbitals).
,5. Which of the following elements has the largest atomic radius?
A) Li
B) Na
C) K
D) Rb
Correct Answer: D
Explanation: Atomic radius increases down a group in the periodic table. Rb
(rubidium) is the largest among the options because it is furthest down Group 1.
6. Which of the following elements has the highest electronegativity?
A) F
B) Cl
C) Br
D) I
Correct Answer: A
Explanation: Electronegativity increases across a period and decreases down a
group. Fluorine (F) is the most electronegative element.
7. A student is studying the rotation of the electron spin in an orbital. According
to the Pauli exclusion principle:
A) Two electrons in the same orbital must have opposite spins
B) Two electrons in the same orbital must have the same spin
C) Electrons can occupy any orbital regardless of spin
D) Only one electron can occupy an orbital
Correct Answer: A
Explanation: The rotation of the electron spin and the Pauli exclusion principle
state that no two electrons in the same atom can have the same set of four
, quantum numbers. Therefore, two electrons in the same orbital must have
opposite spins (+½ and -½).
8. Which of the following is the correct electron configuration for a copper (Cu)
atom (atomic number 29)?
A) [Ar] 4s² 3d⁹
B) [Ar] 4s¹ 3d¹⁰
C) [Ar] 4s² 3d¹⁰
D) [Ar] 4s⁰ 3d¹¹
Correct Answer: B
Explanation: Copper has an anomalous electron configuration: [Ar] 4s¹ 3d¹⁰. This is
because a half-filled or fully filled d subshell is more stable than a partially filled
one. Option C is zinc (Zn).
9. Which of the following best describes the rotation of the electron in the
quantum mechanical model?
A) The electron moves in a fixed circular path
B) The electron's position is described by a probability distribution
C) The electron is stationary
D) The electron moves in a straight line
Correct Answer: B
Explanation: In the quantum mechanical model, the rotation of the electron and
its position are described by a probability distribution (orbital). The electron does
not have a fixed path but exists in a cloud of probability.
10. Which of the following is an example of an alkali metal?
A) Mg
B) Ca
Answers | 2026 Revised Updated | 100%
Correct - Toronto Metropolitan University.
CHY 103 Final Exam | Full Questions and Answers | 2026 Revised Updated |
100% Correct - Toronto Metropolitan University
SECTION 1: Atomic Structure and Periodicity
1. Which of the following subatomic particles has a relative charge of +1 and a
mass of approximately 1 amu?
A) Electron
B) Proton
C) Neutron
D) Positron
Correct Answer: B
Explanation: The proton has a relative charge of +1 and a mass of approximately 1
atomic mass unit (amu). Electrons have a charge of -1 and negligible mass.
Neutrons have no charge and a mass of approximately 1 amu.
2. An atom of carbon-14 has how many neutrons?
A) 6
B) 8
,C) 14
D) 20
Correct Answer: B
Explanation: Carbon-14 has an atomic number of 6 (6 protons) and a mass
number of 14. The number of neutrons is 14 - 6 = 8.
3. Which of the following is the correct electron configuration for a neutral
oxygen atom (atomic number 8)?
A) 1s² 2s² 2p⁴
B) 1s² 2s² 2p⁶
C) 1s² 2s² 2p³
D) 1s² 2s² 2p⁵
Correct Answer: A
Explanation: Oxygen has 8 electrons. The electron configuration is 1s² 2s² 2p⁴.
Option B is neon (10 electrons), Option C is nitrogen (7 electrons), and Option D is
fluorine (9 electrons).
4. A student is studying the rotation of the electron around the nucleus.
According to the Bohr model, electrons:
A) Move in fixed circular orbits around the nucleus
B) Are randomly distributed around the nucleus
C) Exist in a cloud of probability
D) Are stationary
Correct Answer: A
Explanation: The rotation of the electron around the nucleus in the Bohr model
occurs in fixed circular orbits with quantized energy levels. The quantum
mechanical model describes electrons in probability clouds (orbitals).
,5. Which of the following elements has the largest atomic radius?
A) Li
B) Na
C) K
D) Rb
Correct Answer: D
Explanation: Atomic radius increases down a group in the periodic table. Rb
(rubidium) is the largest among the options because it is furthest down Group 1.
6. Which of the following elements has the highest electronegativity?
A) F
B) Cl
C) Br
D) I
Correct Answer: A
Explanation: Electronegativity increases across a period and decreases down a
group. Fluorine (F) is the most electronegative element.
7. A student is studying the rotation of the electron spin in an orbital. According
to the Pauli exclusion principle:
A) Two electrons in the same orbital must have opposite spins
B) Two electrons in the same orbital must have the same spin
C) Electrons can occupy any orbital regardless of spin
D) Only one electron can occupy an orbital
Correct Answer: A
Explanation: The rotation of the electron spin and the Pauli exclusion principle
state that no two electrons in the same atom can have the same set of four
, quantum numbers. Therefore, two electrons in the same orbital must have
opposite spins (+½ and -½).
8. Which of the following is the correct electron configuration for a copper (Cu)
atom (atomic number 29)?
A) [Ar] 4s² 3d⁹
B) [Ar] 4s¹ 3d¹⁰
C) [Ar] 4s² 3d¹⁰
D) [Ar] 4s⁰ 3d¹¹
Correct Answer: B
Explanation: Copper has an anomalous electron configuration: [Ar] 4s¹ 3d¹⁰. This is
because a half-filled or fully filled d subshell is more stable than a partially filled
one. Option C is zinc (Zn).
9. Which of the following best describes the rotation of the electron in the
quantum mechanical model?
A) The electron moves in a fixed circular path
B) The electron's position is described by a probability distribution
C) The electron is stationary
D) The electron moves in a straight line
Correct Answer: B
Explanation: In the quantum mechanical model, the rotation of the electron and
its position are described by a probability distribution (orbital). The electron does
not have a fixed path but exists in a cloud of probability.
10. Which of the following is an example of an alkali metal?
A) Mg
B) Ca
