CHEM 1411 - Chapter 7 quiz
What is the electron group (EG) and molecular geometry (MG) of an ammonium ion?
(EG) tetrahedral and (MG) tetrahedral
What is the electron group (EC) and molecular geometry (MG) of an ammonia molecule?
(EG) tetrahedral and (MG) trigonal pyramidal
How many polar bonds does CH4 contain?
0
Draw the molecule NH3. What are the bond angles in the structure?
107°
Draw the molecule CH4 . What are the bond angles in the structure?
109.5°
Construct the molecule PF5 using a molecular modeling software such as Spartan or 3D-ChemDraw. What are the bond angles of the equatorial fluorine's in the structure?
120°
How many electrons are shared in a single covalent bond?
2
How many electrons are shared in a double covalent bond?
4
How many polar bonds does CCl4 have in its structure?
4
The halogens have how many valence electrons?
7
Construct the molecule IF5 using a molecular modeling software such as Spartan or 3D-ChemDraw. What are the bond angles of the equatorial fluorine's in the structure?
90°
Draw the dot structure for PF5 . What are the bond angles of the axial fluorine's in the structure?
90°
Which compound has only ionic bonds?
Al2O3
According to VSEPR theory, the shape of an ammonium ion, NH4+, is most similar to __________.
CH4
The bond angles in CH4, NH3, and H2O are 109.5°, 107°, and 104.5°, respectfully. Which of the statements best describes the variance in bond angles?
CH4 has no lone pairs of electrons on the central atom so the optimal molecular shape would be tetrahedral with bond angles of 109.5°. In NH3 and H2O there are 1 and 2 lone pairs, respectfully, so more repulsion exists between the bonds and lone pairs, as a result, the bond angles are less than 109.5°.
Which molecule has only covalent bonds?
CO2
A molecule that has a single covalent bond is _____.
Cl2
Why are detergents and soaps good at cleaning up oily stains from dishes or clothing?
Detergents and soaps work well to clean up oily messes because they are amphiphilic in nature so they contain both hydrophilic (polar) and hydrophobic (non-polar) ends. The hydrophobic end attaches to oils via London forces creating micelles which leave the hydrophilic part exposed and can be washed away by water.
According to periodic trends, which element is the most electronegative?
F
Draw the dot structures for IF5 and PF5 . How do the molecular shapes differ?
In PF5 there is a lone pair of electrons on phosphorus where as in IF5 there are no lone pairs on iodine. As a result, the molecular shape of PF5 is square pyramidal and IF5 is trigonal bipyramidal.
Which of the following pairs of elements can be joined by a covalent bond?
N and C
A diatomic molecule with a triple covalent bond is _____.
N2
Which of the following molecules has the greatest bond energy?
N2
Which of the following is an ionic compound?
Na2O
Which of the following diatomic molecules is joined by a double covalent bond?
O2
Based off periodic trends, which of the following has the strongest lattice energy?
aluminum chloride
In an ionic bond, the charge on the cation (i.e. the metal) is
always positive.
What type of bond will typically form between boron and hydrogen based on their electronegativity?
covalent
Which statement best describes a bond forming between fluorine and iodine?
fluorine is more electronegative than iodine so it will attract the electron density in the bond giving rise to a polar bond
According to the octet rule, a bromine atom has a tendency to
gain one electron.
Using VSEPR theory, predict the molecule shape of a molecule that contains 2 electron groups.
linear
What is the molecular shape of CO2?
linear
According to the octet rule, a magnesium atom has a tendency to _____.
lose two electrons
Based off molecular polarity determined by VSEPR theory, which of the following would be insoluble in CCl4?
methanol
Which one of the following elements does not exist as a diatomic molecule in nature?
neon
Which element contains triple covalent bonds?
nitrogen
Using VSEPR theory, predict the electron group geometry, molecular shape, and the bond angles in a molecule that contains 6 electron groups (5 bonds and 1 lone pair electrons).
octahedral, square pyramidal, 90°
A covalent bond is formed when two atoms
share one or more pairs of electrons with each other.
What is the molecular shape and polarity for Xenon Tetrafluoride?
square-planar and non-polar
According to the octet rule, which element will have a tendency to lose 2 electrons?
strontium
Using VSEPR theory, predict the electron group geometry, molecular shape, and the bond angles in a molecule that contains 4 electron groups (3 bonds and 1 lone pair electrons).
tetrahedral, trigonal pyramidal, < 109.5°
Using VSEPR theory, predict the electron group geometry, molecular shape, and the bond angles in a molecule that contains 5 electron groups (2 bonds and 3 lone pair electrons).
trigonal bipyramidal, linear, 180°
Using VSEPR theory, predict the molecular shape and bond angles in BCl3.
trigonal planer, 120°
