1. What is meant by the polarity of a covalent bond?
A.
Equal sharing of electrons between two atoms
B.
Unequal sharing of electrons between two atoms
C.
Complete transfer of electrons between two atoms
D.
Sharing of protons between two atoms
Correct Answer:
Unequal sharing of electrons between two atoms
Explanation:
A covalent bond is polar when the bonded electrons are shared unequally because the two atoms have different electronegativities.
2. Which bond is most likely to be polar?
A.
H–H
B.
Cl–Cl
C.
H–Cl
D.
N–N
Correct Answer:
H–Cl
Explanation:
The H–Cl bond is polar because chlorine attracts the shared electron pair more strongly than hydrogen.
3. In a polar covalent bond, the atom with higher electronegativity carries which partial charge?
A.
Partial positive charge
B.
Partial negative charge
C.
Complete positive charge
D.
No charge under any condition
Correct Answer:
Partial negative charge
Explanation:
The more electronegative atom attracts the shared electrons toward itself and therefore gets a partial negative charge.
4. Which symbol is commonly used to represent a partial positive charge on an atom?
A.
δ−
B.
δ+
C.
+2
D.
−2
Correct Answer:
δ+
Explanation:
The symbol δ+ indicates that an atom has a partial positive charge due to unequal sharing of bonding electrons.
5. Which of the following bonds is nonpolar covalent?
A.
H–F
B.
O–H
C.
Cl–Cl
D.
H–Cl
Correct Answer:
Cl–Cl
Explanation:
The two chlorine atoms have the same electronegativity, so they share the bonding electrons equally and form a nonpolar covalent bond.
6. The polarity of a covalent bond mainly depends on the difference in which property of the bonded atoms?
A.
Atomic mass
B.
Electronegativity
C.
Number of neutrons
D.
Melting point
Correct Answer:
Electronegativity
Explanation:
Bond polarity results from a difference in electronegativity, which determines how strongly each atom attracts the shared electrons.
7. In the H–F bond, which atom has a partial negative charge?
A.
Hydrogen
B.
Fluorine
C.
Both atoms have partial negative charges
D.
Neither atom has a partial charge
Correct Answer:
Fluorine
Explanation:
Fluorine is more electronegative than hydrogen, so it attracts the shared electron pair and becomes partially negative.
8. A bond between two identical atoms is generally:
A.
Polar covalent
B.
Nonpolar covalent
C.
Ionic
D.
Coordinate covalent only
Correct Answer:
Nonpolar covalent
Explanation:
Identical atoms have equal electronegativities and share the bonding electrons equally, producing a nonpolar covalent bond.
9. Which bond has the greater polarity, assuming the atoms are arranged as shown?
A.
C–C
B.
C–H
C.
C–O
D.
O–O
Correct Answer:
C–O
Explanation:
Oxygen is more electronegative than carbon, so the C–O bond has a greater electronegativity difference and is more polar.
10. What happens to bond polarity when the electronegativity difference between two bonded atoms increases?
A.
It generally increases
B.
It always becomes zero
C.
It changes into a metallic bond
D.
It becomes independent of electron sharing
Correct Answer:
It generally increases
Explanation:
A larger electronegativity difference causes more unequal sharing of electrons, resulting in greater bond polarity.
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