GENERAL CHEMISTRY I – FINAL PROCTORED EXAM
60 QUESTIONS & ANSWERS WITH FULL EXPLANATIONS
GENERAL CHEMISTRY · PHARMACOLOGY · PRECALCULUS | LATEST
2026 VERSION
✔ Correct answers highlighted in green · Full explanation provided for every
question
▶ GENERAL CHEMISTRY I
Q1. What is the atomic number of Carbon?
A) 4
✔ B) 6 ← CORRECT ANSWER
C) 8
D) 12
💡 EXPLANATION:
The atomic number represents the number of protons in an atom's
nucleus. Carbon (C) has 6 protons, giving it atomic number 6. This is a
fundamental property that uniquely identifies each element on the periodic
table.
Q2. Which of the following is a physical change?
A) Burning wood
B) Rusting iron
✔ C) Melting ice ← CORRECT ANSWER
D) Digesting food
💡 EXPLANATION:
A physical change alters the form or appearance of matter but does NOT
change its chemical composition. Melting ice (H₂O solid → H₂O liquid) is
physical — the substance remains water. Burning, rusting, and digestion
are chemical changes that produce new substances.
Q3. The SI unit of amount of substance is:
A) Gram
B) Liter
, ✔ C) Mole ← CORRECT ANSWER
D) Kilogram
💡 EXPLANATION:
The mole (mol) is the SI base unit for the amount of substance. One mole
contains exactly 6.022 × 10²³ entities (Avogadro's number). Grams
measure mass, liters measure volume — neither is a unit of 'amount of
substance.'
Q4. Which subatomic particle has a negative charge?
A) Proton
B) Neutron
✔ C) Electron ← CORRECT ANSWER
D) Nucleus
💡 EXPLANATION:
Electrons carry a charge of −1 (−1.602 × 10⁻¹⁹ C). Protons carry a +1
charge, neutrons are neutral (0 charge), and the nucleus is not a
subatomic particle — it is the dense central region containing protons and
neutrons.
Q5. Avogadro's number is approximately:
✔ A) 6.022 × 10²³ ← CORRECT ANSWER
B) 3.14 × 10²³
C) 6.022 × 10²²
D) 1.602 × 10⁻¹⁹
💡 EXPLANATION:
Avogadro's number (Nₐ) = 6.022 × 10²³ mol⁻¹. It defines the number of
atoms, molecules, or formula units in one mole of any substance. Note:
1.602 × 10⁻¹⁹ is the elementary charge in coulombs, not Avogadro's
number.
Q6. What is the chemical formula for water?
A) HO
B) H₂O₂
, ✔ C) H₂O ← CORRECT ANSWER
D) OH₂
💡 EXPLANATION:
Water consists of 2 hydrogen atoms covalently bonded to 1 oxygen atom
→ H₂O. H₂O₂ is hydrogen peroxide (a different compound). HO and OH₂
do not represent stable neutral molecules under normal conditions.
Q7. Which of the following elements is a noble gas?
A) Oxygen
B) Nitrogen
C) Chlorine
✔ D) Neon ← CORRECT ANSWER
💡 EXPLANATION:
Noble gases (Group 18) have completely filled valence electron shells,
making them very stable and largely unreactive. Neon (Ne) is a noble gas.
Oxygen and nitrogen are in Groups 16 and 15 respectively; chlorine is a
halogen (Group 17).
Q8. The periodic table is arranged in order of increasing:
A) Atomic mass
✔ B) Atomic number ← CORRECT ANSWER
C) Electronegativity
D) Density
💡 EXPLANATION:
The modern periodic table, as defined by Moseley's Law, arranges
elements in order of increasing atomic number (number of protons). Earlier
versions used atomic mass (Mendeleev), but atomic number gives a more
accurate and consistent arrangement.
Q9. Which type of bond involves the sharing of electrons?
A) Ionic bond
B) Metallic bond
✔ C) Covalent bond ← CORRECT ANSWER
60 QUESTIONS & ANSWERS WITH FULL EXPLANATIONS
GENERAL CHEMISTRY · PHARMACOLOGY · PRECALCULUS | LATEST
2026 VERSION
✔ Correct answers highlighted in green · Full explanation provided for every
question
▶ GENERAL CHEMISTRY I
Q1. What is the atomic number of Carbon?
A) 4
✔ B) 6 ← CORRECT ANSWER
C) 8
D) 12
💡 EXPLANATION:
The atomic number represents the number of protons in an atom's
nucleus. Carbon (C) has 6 protons, giving it atomic number 6. This is a
fundamental property that uniquely identifies each element on the periodic
table.
Q2. Which of the following is a physical change?
A) Burning wood
B) Rusting iron
✔ C) Melting ice ← CORRECT ANSWER
D) Digesting food
💡 EXPLANATION:
A physical change alters the form or appearance of matter but does NOT
change its chemical composition. Melting ice (H₂O solid → H₂O liquid) is
physical — the substance remains water. Burning, rusting, and digestion
are chemical changes that produce new substances.
Q3. The SI unit of amount of substance is:
A) Gram
B) Liter
, ✔ C) Mole ← CORRECT ANSWER
D) Kilogram
💡 EXPLANATION:
The mole (mol) is the SI base unit for the amount of substance. One mole
contains exactly 6.022 × 10²³ entities (Avogadro's number). Grams
measure mass, liters measure volume — neither is a unit of 'amount of
substance.'
Q4. Which subatomic particle has a negative charge?
A) Proton
B) Neutron
✔ C) Electron ← CORRECT ANSWER
D) Nucleus
💡 EXPLANATION:
Electrons carry a charge of −1 (−1.602 × 10⁻¹⁹ C). Protons carry a +1
charge, neutrons are neutral (0 charge), and the nucleus is not a
subatomic particle — it is the dense central region containing protons and
neutrons.
Q5. Avogadro's number is approximately:
✔ A) 6.022 × 10²³ ← CORRECT ANSWER
B) 3.14 × 10²³
C) 6.022 × 10²²
D) 1.602 × 10⁻¹⁹
💡 EXPLANATION:
Avogadro's number (Nₐ) = 6.022 × 10²³ mol⁻¹. It defines the number of
atoms, molecules, or formula units in one mole of any substance. Note:
1.602 × 10⁻¹⁹ is the elementary charge in coulombs, not Avogadro's
number.
Q6. What is the chemical formula for water?
A) HO
B) H₂O₂
, ✔ C) H₂O ← CORRECT ANSWER
D) OH₂
💡 EXPLANATION:
Water consists of 2 hydrogen atoms covalently bonded to 1 oxygen atom
→ H₂O. H₂O₂ is hydrogen peroxide (a different compound). HO and OH₂
do not represent stable neutral molecules under normal conditions.
Q7. Which of the following elements is a noble gas?
A) Oxygen
B) Nitrogen
C) Chlorine
✔ D) Neon ← CORRECT ANSWER
💡 EXPLANATION:
Noble gases (Group 18) have completely filled valence electron shells,
making them very stable and largely unreactive. Neon (Ne) is a noble gas.
Oxygen and nitrogen are in Groups 16 and 15 respectively; chlorine is a
halogen (Group 17).
Q8. The periodic table is arranged in order of increasing:
A) Atomic mass
✔ B) Atomic number ← CORRECT ANSWER
C) Electronegativity
D) Density
💡 EXPLANATION:
The modern periodic table, as defined by Moseley's Law, arranges
elements in order of increasing atomic number (number of protons). Earlier
versions used atomic mass (Mendeleev), but atomic number gives a more
accurate and consistent arrangement.
Q9. Which type of bond involves the sharing of electrons?
A) Ionic bond
B) Metallic bond
✔ C) Covalent bond ← CORRECT ANSWER
