8 original questions from New Regents. The worksheet, answer key, and browser practice are free.
Lewis Dot Structures 4 questions
Lewis Dot Structures
New Regents original practice • Name: ____________________ Date: __________ Show your work for written answers.
For these neutral molecules, H contributes one valence electron, C contributes four, N contributes five, O contributes six, and Cl contributes seven. One bond line represents two shared electrons. Show lone pairs as dots.
Question 1
How many valence electrons must appear in the Lewis structure of H₂O?
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Question 2
Draw a Lewis structure for H₂O. Show both bonds and all lone pairs.
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Question 3
How many lone pairs are on each Cl atom in the Lewis structure of Cl₂?
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Question 4
In a Lewis structure for CH₄ with four C–H single bonds, explain why no lone pairs are shown on C.
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Checking Models of Ammonia 4 questions
Checking Models of Ammonia
Use the information below to answer questions 5–8.
Ammonia (NH3) contains one N atom bonded to three H atoms. A student proposes three single bonds and leaves the remaining dots off the diagram. Each neutral N atom contributes five valence electrons and each H contributes one.
Question 5
How many electrons are shown by the three N–H bonds in the student's model?
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Question 6
Draw a complete Lewis structure for NH₃. Show all bonds and lone pairs.
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Question 7
A student proposes drawing the missing pair of electrons on one H atom. Explain why the pair belongs on N.
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Question 8
Two nitrogen atoms form N₂. A model shows N≡N with one lone pair on each N. How many total valence electrons does the model show?
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