Multiple Choice Questions
Chemistry: Chemical Bonding and Molecular Structure
Topic: Chemical Bonding and Molecular Structure
Grade: 11
Question 1:
Which of the following molecules has a trigonal pyramidal molecular shape?
A) CH4
B) NH3
C) CO2
D) H2O
Answer: B) NH3
Explanation: NH3 has a trigonal pyramidal molecular shape because it has three bonding pairs and one lone pair of electrons around the central nitrogen atom. This results in a distorted tetrahedral shape. A similar example is PH3 (phosphine) which also has a trigonal pyramidal shape.
Question 2:
Which of the following compounds has the highest boiling point?
A) CH4
B) C2H6
C) C3H8
D) C4H10
Answer: D) C4H10
Explanation: The boiling points of alkanes increase with increasing molecular weight due to stronger London dispersion forces. C4H10 has the highest boiling point among the given compounds as it has the largest number of carbon atoms. Similarly, as the molecular weight increases, the boiling points of alkenes, alcohols, and other organic compounds also increase.
Question 3:
Which of the following molecules has a linear molecular shape?
A) H2O
B) CO2
C) NH3
D) CH4
Answer: B) CO2
Explanation: CO2 has a linear molecular shape because it has two bonding pairs and no lone pairs of electrons around the central carbon atom. The carbon-oxygen double bond forms a linear arrangement. Another example of a molecule with a linear shape is BeCl2 (beryllium chloride).
Question 4:
Which of the following compounds is an example of an ionic compound?
A) H2O
B) CO2
C) NaCl
D) CH4
Answer: C) NaCl
Explanation: NaCl is an example of an ionic compound because it is formed by the transfer of electrons from sodium (Na) to chlorine (Cl). This results in the formation of sodium cations (Na+) and chloride anions (Cl-), which are held together by electrostatic forces of attraction. Ionic compounds generally consist of a metal and a nonmetal.
Question 5:
Which of the following molecules exhibits resonance?
A) O2
B) CO2
C) SO2
D) N2
Answer: C) SO2
Explanation: SO2 exhibits resonance because it has a central sulfur atom bonded to two oxygen atoms and one lone pair of electrons. The double bond between sulfur and one oxygen atom can resonate with the single bond, resulting in resonance structures. Resonance is a phenomenon where a molecule can have multiple Lewis structures with the same arrangement of atoms but different distribution of electrons.
Question 6:
Which of the following compounds has a linear molecular shape?
A) H2O
B) NH3
C) CO2
D) CH4
Answer: C) CO2
Explanation: CO2 has a linear molecular shape because it has two bonding pairs and no lone pairs of electrons around the central carbon atom. The carbon-oxygen double bond forms a linear arrangement. Another example of a molecule with a linear shape is BeCl2 (beryllium chloride).
Question 7:
Which of the following compounds is an example of a covalent compound?
A) NaCl
B) CO2
C) MgO
D) KBr
Answer: B) CO2
Explanation: CO2 is an example of a covalent compound because it is formed by the sharing of electrons between carbon and oxygen atoms. Covalent compounds generally consist of nonmetals and involve the sharing of electrons to achieve a stable electron configuration. In contrast, ionic compounds involve the transfer of electrons between a metal and a nonmetal.
Question 8:
Which of the following elements has the highest electronegativity?
A) Sodium (Na)
B) Oxygen (O)
C) Hydrogen (H)
D) Carbon (C)
Answer: B) Oxygen (O)
Explanation: Oxygen has the highest electronegativity among the given elements. Electronegativity is a measure of an atom\’s ability to attract electrons in a chemical bond. Oxygen has a higher electronegativity compared to sodium, hydrogen, and carbon, which makes it more likely to attract electrons towards itself in a chemical bond.
Question 9:
Which of the following molecules has a bent molecular shape?
A) H2O
B) CO2
C) NH3
D) CH4
Answer: A) H2O
Explanation: H2O has a bent molecular shape because it has two bonding pairs and two lone pairs of electrons around the central oxygen atom. The lone pairs of electrons repel the bonding pairs, resulting in a bent shape. Another example of a molecule with a bent shape is SO2 (sulfur dioxide).
Question 10:
Which of the following compounds is an example of a polar molecule?
A) CO2
B) CH4
C) CCl4
D) H2O
Answer: D) H2O
Explanation: H2O is an example of a polar molecule because it has a bent molecular shape and an electronegativity difference between oxygen and hydrogen atoms. The oxygen atom is more electronegative, resulting in an uneven distribution of charge. This gives rise to a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms.
Question 11:
Which of the following elements has the lowest ionization energy?
A) Sodium (Na)
B) Oxygen (O)
C) Hydrogen (H)
D) Carbon (C)
Answer: A) Sodium (Na)
Explanation: Sodium has the lowest ionization energy among the given elements. Ionization energy is the energy required to remove an electron from an atom or ion. Sodium has a lower ionization energy compared to oxygen, hydrogen, and carbon, which means it is easier to remove an electron from a sodium atom.
Question 12:
Which of the following molecules has a tetrahedral molecular shape?
A) H2O
B) CO2
C) NH3
D) CH4
Answer: D) CH4
Explanation: CH4 has a tetrahedral molecular shape because it has four bonding pairs and no lone pairs of electrons around the central carbon atom. The four hydrogen atoms are arranged in a tetrahedral arrangement around the carbon atom. Another example of a molecule with a tetrahedral shape is SiH4 (silane).
Question 13:
Which of the following compounds is an example of a metallic compound?
A) NaCl
B) CO2
C) CuO
D) H2O
Answer: C) CuO
Explanation: CuO is an example of a metallic compound because it consists of metal atoms (copper) held together by metallic bonds. Metallic compounds generally have high melting points, conduct electricity, and are malleable and ductile. In contrast, ionic compounds involve the transfer of electrons between a metal and a nonmetal.
Question 14:
Which of the following molecules has a trigonal planar molecular shape?
A) H2O
B) CO2
C) NH3
D) BF3
Answer: D) BF3
Explanation: BF3 has a trigonal planar molecular shape because it has three bonding pairs and no lone pairs of electrons around the central boron atom. The three fluorine atoms are arranged in a trigonal planar arrangement around the boron atom. Another example of a molecule with a trigonal planar shape is SO3 (sulfur trioxide).
Question 15:
Which of the following compounds is an example of a network solid?
A) NaCl
B) CO2
C) SiO2
D) H2O
Answer: C) SiO2
Explanation: SiO2 is an example of a network solid because it consists of a three-dimensional network of covalent bonds between silicon and oxygen atoms. Network solids have high melting points, are hard and brittle, and do not conduct electricity. In contrast, molecular compounds like CO2 and ionic compounds like NaCl do not have a continuous network of covalent bonds.