CHM 1010 COVALENT COMPOUNDS CHAPTER 4 CONCEPT
QUESTIONS WITH CORRECT ANSWERS (ALL QUESTIONS)
1.A _____ is a discrete group of atoms held together by covalent bonds. - molecule
2.A _________ _____________ shows all of the bonds and nonbonding electrons, but a
____________ _________ does not. –
Blank 1: Lewis
Blank 2: structure
Blank 3: molecular or chemical
Blank 4: structure or formula
3.A covalent bond is a _____-electron bond in which the bonding atoms share their _____
electrons. - two; valence
4.A covalent bond results from the sharing of electrons between/among _____ atoms. - two
5.A mixture of dimethyl ether and propane is used in an over-the-counter device to treat warts,
by freezing them. The structure of dimethyl ether is shown. Is dimethyl ether a polar or nonpolar
molecule? - Polar
Reason:
There is a partial negative charge on the oxygen atom and partial positive charges on the carbon
atoms. These dipoles do not cancel each other because the geometry around the oxygen is bent.
6.An atom with a bent shape is surrounded by _____ atoms and _____ lone pair(s) of electrons -
two; one
two; two
7.An atom with a tetrahedral shape is surrounded by ______ atoms or groups. - four
Covalent compounds are formed by _____, - sharing electrons between atoms
Electronegativity measures - an atom's attraction for electrons in a bond.
How many bonds will boron typically form? - 3
,How many covalent bonds are there in the molecule of SO2 whose structure is shown? - 3
How many covalent bonds are there in the structure shown? - 6
How many electrons are contained in a complete octet of electrons? - 8
How many electrons does boron typically have in its valence shell when it is the central atom in
a Lewis structure? - 6
How many lone pairs of electrons need to be added to the Lewis structure shown?- 0- 9- 11- 18 -
9
How many resonance structure are needed to describe the structure of HNO3? - 2
How many valence electrons are in CH3NH2? - 14
How many valence electrons are in PO33-? - 26
In order for a bond to be nonpolar, the difference in electronegativities of the two atoms is
_____. - <0.5
In the Lewis structure of CHBr3 the central atom is the _____. - carbon
In the molecule shown, which of the following are in the plane of the paper? - H
O of the OH group
C
List the atoms in order of decreasing electronegativity. (Place the lowest electronegativity at the
bottom.) - o
,s,
se
,te
List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the
bottom.) - Na
Al
P
S
List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the
bottom.) - Na, Al, P, S
List the common prefixes in order of increasing number of atoms. (Place the largest number of
atoms on the bottom.) - Tri, penta, hepta, nona,
List the elements below in order of increasing electronegativity. - K
, Ge
As
Br
List the molecular geometries in order of increasing bond angles. (Place the largest bond angles
at the bottom.) - Trigonal pyramid
tetrahedral
trigonal planar
Linear
Match each bond depiction with its correct description. - A solid line---A bond in the plane of the
paper
A wedge---A bond in front of the plane of the paper
A dashed line----A bond behind the plane of the paper
Match each chemical formula given below with its correct name. - NO2- nitrogen dioxide
PCl3- phosphorous trichloride
N2O- dinitrogen monoxide
PCl5- phosphorous pentachloride
Match each element on the left with the number of covalent bonds that it will typically form. - H-
1
Mg-2
B-3
Match each indicated atom with its correct geometry. - 3-Trigonal planar geometry
1-Tetrahedral geometry
2-Trigonal pyramid
Match each molecular formula with its correct geometry.
A. H2C=O
B. COS (C is the central atom)
C. So2 (Sis the central atom)
D. Ph3 - A. Trigonal planar geometry
B. Linear geometry
C. Bent geometry
D. Trigonal pyramid
Match each molecular formula with its correct geometry. - H2C=O---Trigonal planar geometry
COS (C is the central atom.)---Linear geometry
SO2 (S is the central atom.)---Bent geometry
PH3-----Trigonal pyramid
Match the atom with the number of bonds it will commonly form. - Carbon-4
QUESTIONS WITH CORRECT ANSWERS (ALL QUESTIONS)
1.A _____ is a discrete group of atoms held together by covalent bonds. - molecule
2.A _________ _____________ shows all of the bonds and nonbonding electrons, but a
____________ _________ does not. –
Blank 1: Lewis
Blank 2: structure
Blank 3: molecular or chemical
Blank 4: structure or formula
3.A covalent bond is a _____-electron bond in which the bonding atoms share their _____
electrons. - two; valence
4.A covalent bond results from the sharing of electrons between/among _____ atoms. - two
5.A mixture of dimethyl ether and propane is used in an over-the-counter device to treat warts,
by freezing them. The structure of dimethyl ether is shown. Is dimethyl ether a polar or nonpolar
molecule? - Polar
Reason:
There is a partial negative charge on the oxygen atom and partial positive charges on the carbon
atoms. These dipoles do not cancel each other because the geometry around the oxygen is bent.
6.An atom with a bent shape is surrounded by _____ atoms and _____ lone pair(s) of electrons -
two; one
two; two
7.An atom with a tetrahedral shape is surrounded by ______ atoms or groups. - four
Covalent compounds are formed by _____, - sharing electrons between atoms
Electronegativity measures - an atom's attraction for electrons in a bond.
How many bonds will boron typically form? - 3
,How many covalent bonds are there in the molecule of SO2 whose structure is shown? - 3
How many covalent bonds are there in the structure shown? - 6
How many electrons are contained in a complete octet of electrons? - 8
How many electrons does boron typically have in its valence shell when it is the central atom in
a Lewis structure? - 6
How many lone pairs of electrons need to be added to the Lewis structure shown?- 0- 9- 11- 18 -
9
How many resonance structure are needed to describe the structure of HNO3? - 2
How many valence electrons are in CH3NH2? - 14
How many valence electrons are in PO33-? - 26
In order for a bond to be nonpolar, the difference in electronegativities of the two atoms is
_____. - <0.5
In the Lewis structure of CHBr3 the central atom is the _____. - carbon
In the molecule shown, which of the following are in the plane of the paper? - H
O of the OH group
C
List the atoms in order of decreasing electronegativity. (Place the lowest electronegativity at the
bottom.) - o
,s,
se
,te
List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the
bottom.) - Na
Al
P
S
List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the
bottom.) - Na, Al, P, S
List the common prefixes in order of increasing number of atoms. (Place the largest number of
atoms on the bottom.) - Tri, penta, hepta, nona,
List the elements below in order of increasing electronegativity. - K
, Ge
As
Br
List the molecular geometries in order of increasing bond angles. (Place the largest bond angles
at the bottom.) - Trigonal pyramid
tetrahedral
trigonal planar
Linear
Match each bond depiction with its correct description. - A solid line---A bond in the plane of the
paper
A wedge---A bond in front of the plane of the paper
A dashed line----A bond behind the plane of the paper
Match each chemical formula given below with its correct name. - NO2- nitrogen dioxide
PCl3- phosphorous trichloride
N2O- dinitrogen monoxide
PCl5- phosphorous pentachloride
Match each element on the left with the number of covalent bonds that it will typically form. - H-
1
Mg-2
B-3
Match each indicated atom with its correct geometry. - 3-Trigonal planar geometry
1-Tetrahedral geometry
2-Trigonal pyramid
Match each molecular formula with its correct geometry.
A. H2C=O
B. COS (C is the central atom)
C. So2 (Sis the central atom)
D. Ph3 - A. Trigonal planar geometry
B. Linear geometry
C. Bent geometry
D. Trigonal pyramid
Match each molecular formula with its correct geometry. - H2C=O---Trigonal planar geometry
COS (C is the central atom.)---Linear geometry
SO2 (S is the central atom.)---Bent geometry
PH3-----Trigonal pyramid
Match the atom with the number of bonds it will commonly form. - Carbon-4
