Questions on Octet Rule
20 Multiple-Choice Questions: Octet Rule
Questions
1. What does the Octet Rule state?
A) Atoms are stable with 6 electrons in their outer shell
B) Atoms lose electrons to become metals
C) Atoms are most stable with 8 valence electrons
D) Only noble gases follow it
E) It applies only to transition metals
2. Which group of elements naturally satisfies the Octet Rule without bonding?
A) Alkali metals
B) Halogens
C) Noble gases
D) Transition metals
E) Alkaline earth metals
3. Which of the following elements is an exception to the Octet Rule?
A) Neon
B) Oxygen
C) Carbon
D) Hydrogen
E) Sulfur
4. How many valence electrons does an atom need to fulfill the Octet Rule?
A) 2
B) 4
C) 6
D) 8
E) 10
5. What type of bond typically forms when atoms share electrons to satisfy the Octet Rule?
A) Ionic
B) Metallic
C) Hydrogen
D) Covalent
E) Van der Waals
6. Which of the following atoms can exceed the Octet Rule?
A) Carbon
B) Hydrogen
C) Nitrogen
D) Phosphorus
E) Fluorine
7. What is the usual number of valence electrons for oxygen in a stable molecule?
A) 2
B) 4
C) 6
D) 8
E) 10
8. Which element below usually violates the Octet Rule by having less than 8 electrons?
A) Boron
B) Chlorine
C) Phosphorus
D) Argon
E) Iodine
9. Which molecule follows the Octet Rule?
A) BF₃
B) PCl₅
C) NH₃
D) SF₆
E) NO
10. Why is hydrogen an exception to the Octet Rule?
A) It can gain 4 electrons
B) It follows the duet rule with 2 electrons
C) It has no electrons
D) It needs 8 protons
E) It forms metallic bonds only
11. Which atom in the molecule H₂O satisfies the Octet Rule?
A) Hydrogen
B) Both H and O
C) Only oxygen
D) None of them
E) Hydrogen and oxygen have 10 electrons
12. Which molecule disobeys the Octet Rule because it has an odd number of electrons?
A) CO₂
B) CH₄
C) NO
D) NH₃
E) H₂O
13. The Octet Rule explains why atoms:
A) Always become neutral
B) Form ions or share electrons to achieve stability
C) Have the same number of neutrons
D) Always form covalent bonds
E) Exist in elemental form
14. Which element typically does not obey the Octet Rule because it lacks enough electrons?
A) Boron
B) Oxygen
C) Sulfur
D) Nitrogen
E) Fluorine
15. How does sodium achieve an octet in a compound?
A) Sharing electrons
B) Losing one electron
C) Gaining two electrons
D) Breaking covalent bonds
E) Gaining a proton
16. What is the maximum number of valence electrons an atom can have and still follow the Octet Rule?
A) 6
B) 8
C) 12
D) 10
E) 14
17. Which group on the periodic table already has a full octet?
A) Group 1
B) Group 2
C) Group 7
D) Group 8
E) Group 3
18. What causes atoms to form chemical bonds according to the Octet Rule?
A) To increase mass
B) To become isotopes
C) To become unstable
D) To achieve a full valence shell
E) To release energy only
19. Which element can have more than 8 valence electrons due to availability of d-orbitals?
A) Carbon
B) Nitrogen
C) Silicon
D) Sulfur
E) Beryllium
20. Which of these elements is most likely to gain electrons to complete its octet?
A) Lithium
B) Sodium
C) Fluorine
D) Magnesium
E) Beryllium
- Questions on Hund's Rule and Orbital Filling Diagrams
- Questions on Electron Configurations
- Questions on Valence Electrons
Answers and Explanations
1. C) Atoms are most stable with 8 valence electrons
→ This is the basic definition of the Octet Rule.
2. C) Noble gases
→ They naturally have 8 valence electrons, making them stable.
3. D) Hydrogen
→ It only needs 2 electrons (duet rule), not 8.
4. D) 8
→ An octet means eight valence electrons.
5. D) Covalent
→ Atoms share electrons to reach an octet.
6. D) Phosphorus
→ It can expand its octet using d-orbitals.
7. D) 8
→ Oxygen typically follows the Octet Rule.
8. A) Boron
→ It is often stable with only 6 valence electrons.
9. C) NH₃
→ Nitrogen in ammonia has 8 valence electrons.
10. B) It follows the duet rule with 2 electrons
→ Hydrogen is stable with only two electrons.
11. C) Only oxygen
→ Each H has 2 electrons; O reaches 8.
12. C) NO
→ Nitric oxide has an odd number of electrons.
13. B) Form ions or share electrons to achieve stability
→ This is the driving force behind bonding in the Octet Rule.
14. A) Boron
→ Common exception due to electron deficiency.
15. B) Losing one electron
→ Na⁺ achieves the noble gas configuration of neon.
16. B) 8
→ Standard octet limit.
17. D) Group 8
→ These are noble gases with full octets.
18. D) To achieve a full valence shell
→ This promotes chemical bonding.
19. D) Sulfur
→ Can exceed 8 electrons using 3d orbitals.
20. C) Fluorine
→ Highly electronegative, gains one electron to complete octet.
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