Valence Electrons MCQs
Practice Valence Electrons multiple-choice questions from Structure of the Atom (Class 9 Science) - tap an answer for instant feedback and a step-by-step solution. Practice the full set free on the RankByte app.
Valence ElectronsQuiz - Solve & Score
Q1. Before drawing dots for O2, you sum the valence electrons of all its atoms; what number do you obtain?
- A.16
- B.10
- C.12
- D.14
Answer: C. 12
Add the valence electrons of every atom in O2: oxygen(6) + oxygen(6) = 12. That is the total to place in the electron-dot structure.
Q2. If equal stability is reached when potassium bonds with fluorine, the criss-cross rule outputs which formula?
- A.KF
- B.K7F
- C.K2F2
- D.K2F
Answer: A. KF
potassium has valency 1, fluorine has valency 1. Criss-cross the valencies and simplify: the formula is KF.
Q3. A pupil draws the dot symbol for magnesium; how many dots should ring the letter?
- A.3
- B.2
- C.1
- D.12
Answer: B. 2
In a Lewis dot symbol the dots equal the valence electrons. magnesium (2,8,2) has 2 outer electrons, so 2 dots are drawn.
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