Chemistry: Ch. 10
How many electrons are transferred between the cation and anion to form the ionic bond in one formula unit of each compound?
1 electron: KBr, LiF, and NaCl 2 electrons: BaS and CaO
What is the angle between electron groups in the linear electron geometry?
180
Construct an orbital diagram to show the electron configuration for a neutral magnesium atom, Mg.
1s2, 2s2, 2p6, 3s2
Indicate which of the electrons in the electron configuration are shown in the Lewis structure. 1s22s22p63s23p64s23d104p6−−−5s1 1s22s22p63s23p64s2−−−3d104p65s1−−− 1s22s22p63s23p64s23d104p65s1−−− 1s22s22p63s23p64s23d104p65s1−−−−−−
1s22s22p63s23p64s23d104p65s1−−−
Indicate which of the electrons in the electron configuration are shown in the Lewis structure. 1s22s22p63s23p64s2−−−3d104p6 1s22s22p63s2−−−3p64s23d104p6−−− 1s22s22p63s23p64s23d104p6−−− 1s22s22p63s23p64s2−−−3d104p6−−−
1s22s22p63s23p64s2−−−3d104p6−−−
How many resonance structures exist for the formate ion, HCO2-?
2
How many total valence electrons are in the Lewis structure of NO3−? 23 24 25 26
24
How many valence electrons are in the nitrate ion?
24
How many bonding electrons are in the Lewis structure of N2?
6
How many bonding electrons are in the Lewis structure of carbon monoxide, CO?
6
Which bond is polar? A bond between N and Cl A bond between Cl and Cl A bond between H and Cl A bond between H and Te
A bond between H and Cl
In a Lewis structure, a dash drawn between two atoms represents _______________. a non-bonding pair of electrons a shared electron pair a single electron an octet
A shared electron pair
How do you determine the number of electrons that go into the Lewis structure of a molecule? Add up the lone pairs from each atom that is forming the molecule. Add up the valence electrons from each atom that is forming the molecule. Add up the electrons involved in the formation of covalent bonds. Add up the electrons involved in the formation of covalent and ionic bonds.
Add up the valence electrons from each atom that is forming the molecule.
Use Lewis theory to determine the formula for the compound that forms from Al and S.
Al2S3
Which atom has a Lewis structure with an octet? Na Ar Mg Cl
Ar
Which of the following statements are TRUE about the BF3 molecule?
BF3 has a trigonal planar molecular geometry. BF3 is nonpolar. BF3 violates the octet rule for the central atom.
Use Lewis theory to determine the formula for the compound that forms from Ba and F.
BaF2
ClO−2 tetrahedral bent trigonal planar trigonal pyramidal linear
Bent
Determine the molecular geometry of H2S. trigonal planar trigonal pyramidal linear tetrahedral bent
Bent
Determine the molecular geometry of SO2. bent linear tetrahedral trigonal planar trigonal pyramidal
Bent
Electronegativity Difference 0-0.4 0.4-2.0 2.0 +
Bond Type pure covalent (non-polar) polar covalent ionic
Use the Lewis model to predict the correct formula for the compound that forms between Ca and Br. Ca2Br CaBr2 Ca2Br2 CaBr
CaBr2
Use the Lewis model to explain why the compound that forms between hydrogen and sulfur has the formula H2S.
Each H atom in a compound can contribute 1 valence e−, a S atom contributes 6 valence e−. When H2S forms, each H atom shares their 1e− with S and in doing so has achieved a stable duet. The S atom started with 6 valence electrons, and upon forming bonds with H atoms, it achieves a stable octet.
Electron groups: 2 Bonding groups: 2 Lone pairs: 0
Electron geometry: Linear Angle: 180 Molecular geometry: Linear
Bonding groups: 4 Lone pairs: 0
Electron geometry: Tetrahedral Angle: 109.5 Molecular geometry: Tetrahedral
Bonding groups: 2 Lone pairs: 2
Electron geometry: Tetrahedral Angle: 109.5 Molecular: Bent
Bonding groups: 3 Lone pairs: 1
Electron geometry: Tetrahedral Angle: 109.5 Molecular: Trigonal pyramidal
Bonding groups: 2 Lone pairs: 1
Electron geometry: Trigonal planar Angle: 120 Molecular geometry: Bent
Bonding groups: 3 Lone pairs: 0
Electron geometry: Trigonal planar Angle: 120 Molecular geometry: Trigonal planar
Which of these molecules or ions exhibit resonance?
Exhibit: O3 and CO32- Do not exhibit: CCl4 and H2O
When you have 4 electron groups and none of them are lone pairs, the molecular geometry is trigonal pyramidal.
False
Which scientist developed a model that can be used to predict the structure of a molecule? John Dalton G.N. Lewis Joseph Proust Ernest Rutherford
G.N. Lewis
Which molecule listed below has a nonpolar covalent bond?
H2
Which molecule listed below has a polar covalent bond?
H2O
Which molecule listed below is a polar molecule?
HCN, NH3, and H2O
Consider the following electronegativity values: H = 2.1 , Cl = 3.0 , F = 4.0 Which molecule below would you expect to have the more polar bond?
HF
Match each ion with the noble gas whose electron configuration it shares.
He: Li+ and Be2+ Ne: O2-, Na+, and N3- Ar: Cl-, Ca2+, and S2-
Which of the following atoms would most likely be terminal in a Lewis structure? helium hydrogen carbon boron
Hydrogen
If a molecule has polar bonds, is the molecule itself polar? Yes, if a molecule has polar bonds, the molecule is always polar. No, if a molecule has polar bonds, the molecule is always nonpolar. If a molecule has polar bonds, the molecule can be either polar or nonpolar.
If a molecule has polar bonds, the molecule can be either polar or nonpolar.
Determine the electron geometry of N2O (oxygen is terminal). linear hexahedral tetrahedral pentahedral trigonal planar
Linear
Determine the molecular geometry of N2O (oxygen is terminal). trigonal pyramidal bent tetrahedral trigonal planar linear
Linear
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for two electron groups? trigonal planar pentahedral tetrahedral linear hexahedral
Linear
What is the molecular geometry of N2O (Nitrogen is the central atom.)? Bent Trigonal pyramidal Linear Tetrahedral
Linear
Use Lewis theory to determine the formula for the compound that forms from Na and S.
Na2S
Which of the following compounds have resonance structures?
O3
Which nonmetals could form an ionic compound with magnesium with the formula MgX2 (where X represents the nonmetal)?
Possible: F, Br, and Cl Not possible: N, S, and O
Which molecule is polar? SiCl4 SCl2 CF4 CS2
SCl2
Which of the following is an exception to the octet rule? Ignore that hydrogen has a duet. CO2 NH4 + H2O SF6
SF6
Use Lewis theory to determine the formula for the compound that forms from Sr and Se.
SrSe
Determine the electron geometry of H2S. hexahedral trigonal planar linear tetrahedral pentahedral
Tetrahedral
Determine the electron geometry of PF3. pentahedral tetrahedral trigonal planar hexahedral linear
Tetrahedral
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for four electron groups? tetrahedral pentahedral linear hexahedral trigonal planar
Tetrahedral
NH+4 linear bent tetrahedral trigonal planar trigonal pyramidal
Tetrahedral
Why?
The two requirements of a polar molecule are: the molecule must have polar bonds and the polar bonds must be distributed asymmetrically, otherwise they cancel out.
What happens if you try to mix a polar liquid with a nonpolar one? They will separate to form two distinct regions. They will react to form a new compound. They will mix to form a homogeneous solution. They will change their dipole moments.
They will separate to form two distinct regions
CO2−3 trigonal planar linear bent trigonal pyramidal tetrahedral
Trigonal planar
Determine the electron geometry of SO2. linear trigonal planar pentahedral hexahedral tetrahedral
Trigonal planar
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for three electron groups? pentahedral linear hexahedral tetrahedral trigonal planar
Trigonal planar
NO−3 trigonal pyramidal linear trigonal planar bent tetrahedral
Trigonal planar
Determine the molecular geometry of PF3. bent trigonal pyramidal trigonal planar tetrahedral linear
Trigonal pyramidal
What is the molecular geometry of PBr3? Trigonal pyramidal Bent Tetrahedral Linear
Trigonal pyramidal
The VSEPR theory predicts that the angle between the central carbon atom and the two oxygen atoms in CO2 measures 180°.
True
Which of the following description best describes the type of electrons used to write a Lewis structure? excited electrons core electrons valence ground state electrons
Valence
To form a stable ion, will magnesium gain or lose electrons? How many electrons?
Will lose two electrons
The electronegativity value for Mg is 1.2 and the value for O is 3.5. Based on these values, what type of bond is expected for a compound formed between Mg and O?
ionic
CS2
linear
Would you expect H3S to be stable? yes no
no
Would you expect HS to be stable? yes no
no
The correct Lewis structure for BF3 would be exactly:
no double bonds
CBr4
tetrahedral
What is the molecular geometry if you have 4 single bonds around the central atom?
tetrahedral
What is the molecular geometry of CCl4?
tetrahedral
The electron geometry and the molecular geometry of ammonia (NH3) are, respectively:
tetrahedral, trigonal pyramidal
BH3
trigonal planar
H2CO
trigonal planar
What is the electron geometry if you have 3 electron groups around the center atom?
trigonal pyramidal
The elements with the highest electronegativity values tend to be found in the:
upper right-side of the periodic table.
Which of the following symbols are used to illustrate commonalities between two or more resonance structures? → = ↔ ⇋
↔