Questions on Valence Electrons
20 Multiple-Choice Questions on Valence Electrons
1. What are valence electrons?
A) Electrons found in the innermost energy level
B) Electrons that participate in nuclear reactions
C) Electrons located in the outermost energy level
D) Protons that behave like electrons
E) Electrons that never form bonds
2. How many valence electrons does a carbon atom have?
A) 2
B) 4
C) 6
D) 8
E) 10
3. Which of the following elements has 7 valence electrons?
A) Oxygen
B) Fluorine
C) Neon
D) Lithium
E) Carbon
4. What group on the periodic table contains elements with a full outer shell of valence electrons?
A) Group 1
B) Group 2
C) Group 17
D) Group 18
E) Group 16
5. How many valence electrons does sulfur (S) have?
A) 2
B) 4
C) 6
D) 8
E) 10
6. Sodium (Na) is in Group 1. How many valence electrons does it have?
A) 0
B) 1
C) 2
D) 7
E) 8
7. Which of the following elements has 2 valence electrons?
A) Beryllium
B) Oxygen
C) Nitrogen
D) Fluorine
E) Neon
8. How many valence electrons does chlorine (Cl) have?
A) 3
B) 5
C) 6
D) 7
E) 8
9. Which of the following statements is true about valence electrons and chemical reactivity?
A) More valence electrons always make elements less reactive.
B) Elements with 8 valence electrons are the most reactive.
C) Reactivity is unrelated to valence electrons.
D) Elements with 1 or 7 valence electrons tend to be highly reactive.
E) All elements with even atomic numbers are unreactive.
10. How many valence electrons does nitrogen have?
A) 3
B) 4
C) 5
D) 6
E) 7
11. Which element has only one valence electron and is located in the second period?
A) Hydrogen
B) Lithium
C) Beryllium
D) Helium
E) Neon
12. What determines the number of valence electrons an element has?
A) Atomic mass
B) Atomic number
C) Energy level
D) Group number
E) Number of protons
13. How many valence electrons does phosphorus (P) have?
A) 3
B) 4
C) 5
D) 6
E) 7
14. Which group on the periodic table contains elements with 2 valence electrons?
A) Group 1
B) Group 2
C) Group 3
D) Group 17
E) Group 18
15. Which of the following noble gases has 2 valence electrons?
A) Helium
B) Neon
C) Argon
D) Krypton
E) Xenon
16. The maximum number of valence electrons an atom can have in the s and p orbitals is:
A) 2
B) 6
C) 8
D) 10
E) 12
17. Which of the following elements has 8 valence electrons in its ground state?
A) Oxygen
B) Argon
C) Hydrogen
D) Sodium
E) Sulfur
18. How many valence electrons are in a silicon (Si) atom?
A) 2
B) 3
C) 4
D) 5
E) 6
19. Why are valence electrons important in chemistry?
A) They affect the color of elements
B) They determine the nucleus size
C) They dictate chemical bonding and reactivity
D) They are found only in radioactive elements
E) They increase atomic mass
20. Which of the following has 0 valence electrons?
A) Helium
B) Hydrogen
C) Neon
D) Beryllium
E) None of the above
- Questions on Pauli Exclusion Principle
- Questions on Hund's Rule and Orbital Filling Diagrams
- Questions on Electron Configurations
Answers and Explanations
1. C – Valence electrons are in the outermost shell.
2. B – Carbon: 1s² 2s² 2p² → 4 valence electrons.
3. B – Fluorine is in Group 17 → 7 valence electrons.
4. D – Group 18 elements (noble gases) have full outer shells.
5. C – Sulfur is in Group 16 → 6 valence electrons.
6. B – Sodium is Group 1 → 1 valence electron.
7. A – Beryllium (Group 2) has 2 valence electrons.
8. D – Chlorine (Group 17) has 7 valence electrons.
9. D – Highly reactive elements often have 1 or 7 valence electrons.
10. C – Nitrogen (Group 15) → 5 valence electrons.
11. B – Lithium is in Period 2, Group 1 → 1 valence electron.
12. D – The group number tells the number of valence electrons.
13. C – Phosphorus (Group 15) → 5 valence electrons.
14. B – Group 2 elements (alkaline earth metals) have 2 valence electrons.
15. A – Helium has 2 electrons, both in its only energy level.
16. C – s (2) + p (6) orbitals = max 8 valence electrons.
17. B – Argon is a noble gas with full outer shell → 8 electrons.
18. C – Silicon (Group 14) has 4 valence electrons.
19. C – Valence electrons determine bonding and chemical reactivity.
20. E – All given elements have at least one valence electron.
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