CHEM 1045 FINAL EXAM LATEST 2026 UPDATE
FAST REVIWED FROM ACTUAL TEST 100
QUESTIONS AND 100% VERIFIED ANSWERS| A+
GRADE Q&A | INSTANT DOWNLOAD PDF
Table of Contents
1. Atomic Structure and Periodicity (Q1–Q10)
2. Chemical Bonding and Molecular Geometry (Q11–Q20)
3. Stoichiometry and Chemical Reactions (Q21–Q30)
4. Thermochemistry and Thermodynamics (Q31–Q35)
5. Chemical Kinetics (Q36–Q38)
6. Chemical Equilibrium (Q39–Q42)
7. Acids and Bases (Q43–Q46)
8. Electrochemistry (Q47–Q50)
Atomic Structure and Periodicity (Q1–Q10)
Q1: What is the atomic number and mass number of an element with 15 protons, 16 neutrons,
and 15 electrons?
A1: Atomic number = 15, Mass number = 31.
The atomic number equals the number of protons. Mass number equals protons +
neutrons.
Q2: How does ionization energy change across a period?
A2: Ionization energy increases across a period.
Electrons are held more tightly as nuclear charge increases across a period.
Q3: Define isotopes.
A3: Isotopes are atoms of the same element with the same number of protons but different
numbers of neutrons.
They have nearly identical chemical properties but different masses.
Q4: What is the electron configuration of sulfur (S)?
A4: 1s² 2s² 2p⁶ 3s² 3p⁴.
Electrons fill orbitals following the Aufbau principle.
Q5: Explain the trend in atomic radius across a period.
A5: Atomic radius decreases across a period.
Increasing nuclear charge pulls electrons closer to the nucleus.
, Q6: What is the difference between a cation and an anion?
A6: A cation is a positively charged ion, an anion is a negatively charged ion.
Cations lose electrons, anions gain electrons.
Q7: What is the first ionization energy of oxygen relative to nitrogen?
A7: Oxygen has slightly lower first ionization energy than nitrogen.
Due to electron-electron repulsion in oxygen’s paired p-orbital electrons.
Q8: Name the element with electron configuration [Ne] 3s² 3p³.
A8: Phosphorus (P).
It has five valence electrons in the 3rd period.
Q9: Define effective nuclear charge (Z_eff).
A9: Effective nuclear charge is the net positive charge experienced by an electron in a multi-
electron atom.
It accounts for shielding by inner electrons.
Q10: How does electronegativity change down a group?
A10: Electronegativity decreases down a group.
Outer electrons are farther from the nucleus and experience less attraction.
Chemical Bonding and Molecular Geometry (Q11–Q20)
Q11: Describe ionic bonding.
A11: Ionic bonding is the electrostatic attraction between oppositely charged ions.
Typically occurs between metals and nonmetals.
Q12: What is the shape of a molecule with four bonding pairs and no lone pairs?
A12: Tetrahedral.
Bond angles are approximately 109.5°.
Q13: Define covalent bond.
A13: A covalent bond is a bond formed by sharing electrons between two nonmetals.
Electron sharing achieves a stable octet for both atoms.
Q14: What type of hybridization occurs in methane (CH₄)?
A14: sp³ hybridization.
One s orbital and three p orbitals combine to form four equivalent sp³ orbitals.
Q15: How does bond polarity arise?
A15: Bond polarity arises from differences in electronegativity between two bonded atoms.
Unequal sharing of electrons leads to a dipole moment.
FAST REVIWED FROM ACTUAL TEST 100
QUESTIONS AND 100% VERIFIED ANSWERS| A+
GRADE Q&A | INSTANT DOWNLOAD PDF
Table of Contents
1. Atomic Structure and Periodicity (Q1–Q10)
2. Chemical Bonding and Molecular Geometry (Q11–Q20)
3. Stoichiometry and Chemical Reactions (Q21–Q30)
4. Thermochemistry and Thermodynamics (Q31–Q35)
5. Chemical Kinetics (Q36–Q38)
6. Chemical Equilibrium (Q39–Q42)
7. Acids and Bases (Q43–Q46)
8. Electrochemistry (Q47–Q50)
Atomic Structure and Periodicity (Q1–Q10)
Q1: What is the atomic number and mass number of an element with 15 protons, 16 neutrons,
and 15 electrons?
A1: Atomic number = 15, Mass number = 31.
The atomic number equals the number of protons. Mass number equals protons +
neutrons.
Q2: How does ionization energy change across a period?
A2: Ionization energy increases across a period.
Electrons are held more tightly as nuclear charge increases across a period.
Q3: Define isotopes.
A3: Isotopes are atoms of the same element with the same number of protons but different
numbers of neutrons.
They have nearly identical chemical properties but different masses.
Q4: What is the electron configuration of sulfur (S)?
A4: 1s² 2s² 2p⁶ 3s² 3p⁴.
Electrons fill orbitals following the Aufbau principle.
Q5: Explain the trend in atomic radius across a period.
A5: Atomic radius decreases across a period.
Increasing nuclear charge pulls electrons closer to the nucleus.
, Q6: What is the difference between a cation and an anion?
A6: A cation is a positively charged ion, an anion is a negatively charged ion.
Cations lose electrons, anions gain electrons.
Q7: What is the first ionization energy of oxygen relative to nitrogen?
A7: Oxygen has slightly lower first ionization energy than nitrogen.
Due to electron-electron repulsion in oxygen’s paired p-orbital electrons.
Q8: Name the element with electron configuration [Ne] 3s² 3p³.
A8: Phosphorus (P).
It has five valence electrons in the 3rd period.
Q9: Define effective nuclear charge (Z_eff).
A9: Effective nuclear charge is the net positive charge experienced by an electron in a multi-
electron atom.
It accounts for shielding by inner electrons.
Q10: How does electronegativity change down a group?
A10: Electronegativity decreases down a group.
Outer electrons are farther from the nucleus and experience less attraction.
Chemical Bonding and Molecular Geometry (Q11–Q20)
Q11: Describe ionic bonding.
A11: Ionic bonding is the electrostatic attraction between oppositely charged ions.
Typically occurs between metals and nonmetals.
Q12: What is the shape of a molecule with four bonding pairs and no lone pairs?
A12: Tetrahedral.
Bond angles are approximately 109.5°.
Q13: Define covalent bond.
A13: A covalent bond is a bond formed by sharing electrons between two nonmetals.
Electron sharing achieves a stable octet for both atoms.
Q14: What type of hybridization occurs in methane (CH₄)?
A14: sp³ hybridization.
One s orbital and three p orbitals combine to form four equivalent sp³ orbitals.
Q15: How does bond polarity arise?
A15: Bond polarity arises from differences in electronegativity between two bonded atoms.
Unequal sharing of electrons leads to a dipole moment.
