StraighterLine General Chemistry I Quiz
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales
2025|2026 Q&A | Instant Download Pdf
1. What is the atomic number of oxygen?
a) 6
b) 7
c) 8
d) 16
Rationale: The atomic number represents the number of protons in an
element; oxygen has 8 protons.
2. Which of the following is a chemical change?
a) Melting ice
b) Rusting iron
c) Boiling water
d) Dissolving sugar
,Rationale: Rusting iron forms a new substance (iron oxide), indicating a
chemical change.
3. How many electrons does a neutral atom of carbon have?
a) 4
b) 6
c) 6
d) 12
Rationale: A neutral carbon atom has 6 protons, so it also has 6 electrons.
4. What type of bond is formed by the sharing of electrons between
atoms?
a) Ionic
b) Covalent
c) Hydrogen
d) Metallic
Rationale: Covalent bonds involve the sharing of electrons between atoms.
5. Which element is a halogen?
a) Oxygen
b) Nitrogen
c) Chlorine
d) Sodium
Rationale: Halogens are group 17 elements; chlorine is a member of this
group.
,6. Which of the following is an example of an exothermic process?
a) Melting ice
b) Combustion of gasoline
c) Evaporation of water
d) Boiling water
Rationale: Exothermic processes release energy; combustion releases heat.
7. The mass number of an atom is the sum of:
a) Protons only
b) Electrons only
c) Protons and neutrons
d) Protons, neutrons, and electrons
Rationale: Mass number = protons + neutrons, as electrons have negligible
mass.
8. Which state of matter has a definite volume but no definite shape?
a) Solid
b) Liquid
c) Gas
d) Plasma
Rationale: Liquids take the shape of their container but maintain a
constant volume.
9. What is the chemical formula for water?
a) CO₂
b) H₂
, c) H₂O
d) O₂
Rationale: Water consists of two hydrogen atoms bonded to one oxygen
atom.
10. Which of the following is an alkali metal?
a) Calcium
b) Magnesium
c) Sodium
d) Aluminum
Rationale: Alkali metals are group 1 elements; sodium is in this group.
11. The electron configuration of a neutral oxygen atom is:
a) 1s² 2s² 2p⁴
b) 1s² 2s² 2p³
c) 1s² 2s² 2p⁴
d) 1s² 2s² 2p⁶
Rationale: Oxygen has 8 electrons: 2 in 1s, 2 in 2s, 4 in 2p.
12. Which of the following represents an ionic compound?
a) CO₂
b) NaCl
c) CH₄
d) H₂O
Rationale: Ionic compounds consist of metals and nonmetals; NaCl is
formed by Na⁺ and Cl⁻ ions.
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales
2025|2026 Q&A | Instant Download Pdf
1. What is the atomic number of oxygen?
a) 6
b) 7
c) 8
d) 16
Rationale: The atomic number represents the number of protons in an
element; oxygen has 8 protons.
2. Which of the following is a chemical change?
a) Melting ice
b) Rusting iron
c) Boiling water
d) Dissolving sugar
,Rationale: Rusting iron forms a new substance (iron oxide), indicating a
chemical change.
3. How many electrons does a neutral atom of carbon have?
a) 4
b) 6
c) 6
d) 12
Rationale: A neutral carbon atom has 6 protons, so it also has 6 electrons.
4. What type of bond is formed by the sharing of electrons between
atoms?
a) Ionic
b) Covalent
c) Hydrogen
d) Metallic
Rationale: Covalent bonds involve the sharing of electrons between atoms.
5. Which element is a halogen?
a) Oxygen
b) Nitrogen
c) Chlorine
d) Sodium
Rationale: Halogens are group 17 elements; chlorine is a member of this
group.
,6. Which of the following is an example of an exothermic process?
a) Melting ice
b) Combustion of gasoline
c) Evaporation of water
d) Boiling water
Rationale: Exothermic processes release energy; combustion releases heat.
7. The mass number of an atom is the sum of:
a) Protons only
b) Electrons only
c) Protons and neutrons
d) Protons, neutrons, and electrons
Rationale: Mass number = protons + neutrons, as electrons have negligible
mass.
8. Which state of matter has a definite volume but no definite shape?
a) Solid
b) Liquid
c) Gas
d) Plasma
Rationale: Liquids take the shape of their container but maintain a
constant volume.
9. What is the chemical formula for water?
a) CO₂
b) H₂
, c) H₂O
d) O₂
Rationale: Water consists of two hydrogen atoms bonded to one oxygen
atom.
10. Which of the following is an alkali metal?
a) Calcium
b) Magnesium
c) Sodium
d) Aluminum
Rationale: Alkali metals are group 1 elements; sodium is in this group.
11. The electron configuration of a neutral oxygen atom is:
a) 1s² 2s² 2p⁴
b) 1s² 2s² 2p³
c) 1s² 2s² 2p⁴
d) 1s² 2s² 2p⁶
Rationale: Oxygen has 8 electrons: 2 in 1s, 2 in 2s, 4 in 2p.
12. Which of the following represents an ionic compound?
a) CO₂
b) NaCl
c) CH₄
d) H₂O
Rationale: Ionic compounds consist of metals and nonmetals; NaCl is
formed by Na⁺ and Cl⁻ ions.
