Lewis structures
What is the total number of valence electrons in a molecule of CO₂?
16 Valence Electrons
What is the molecular geometry of CH₄?
Tetrahedral
What is the bond angle in a tetrahedral molecule?
109.5°.
Is CO₂ polar or nonpolar?
Nonpolar
What is the trend for atomic radius across a period?
Decreases.
What is the Lewis structure of NH₃?
Central nitrogen atom with three single bonds to hydrogen and one lone pair.
What is the molecular geometry of H₂O?
Bent
What is the bond angle in a trigonal planar molecule?
120°.
Is H₂O polar or nonpolar?
Polar
What is the trend for ionization energy down a group?
Decreases.
How many double bonds are in the Lewis structure of O₃ (ozone)?
One
What is the electron geometry of PCl₅?
Trigonal bipyramidal.
What is the bond angle in a bent molecule with 2 lone pairs, like H₂O?
Approximately 104.5°.
Why is CH₄ nonpolar despite having polar bonds?
The symmetrical tetrahedral geometry cancels dipole moments.
What is the trend for electronegativity across a period?
Increases.
What is the formal charge on each oxygen atom in the carbonate ion (CO₃²⁻)?
-1 for one oxygen, 0 for the others
What is the molecular geometry of SF₆?
Octahedral
Why are bond angles in NH₃ slightly less than 109.5°?
Lone pair-bond pair repulsion compresses the angle to about 107°.
What makes a molecule polar?
Unequal sharing of electrons (electronegativity difference) and asymmetrical geometry.
Which element has the highest electronegativity?
Fluorine.
Which element violates the octet rule in BF₃?
Boron.
What is the molecular geometry of XeF₂?
Linear.
What are the bond angles in a trigonal bipyramidal molecule?
90°, 120°, and 180°.
Predict whether SF₄ is polar or nonpolar.
Polar (asymmetric geometry).
Arrange Na, Al, and Cl in order of increasing atomic size.
Cl < Al < Na.