Chemical Bonding Practice Questions
20 free Chemical Bonding practice questions for the General Science. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which type of chemical bond is formed by the complete transfer of one or more electrons from one atom to another?
- A Covalent bond
- B Ionic bond
- C Metallic bond
- D Pi bond
Correct answer: Ionic bond
An ionic bond occurs when a metal atom loses electrons to a non-metal atom, resulting in the formation of oppositely charged ions. These ions are held together by strong electrostatic forces of attraction.
In a coordinate covalent bond (dative bond), how are the shared electrons provided?
- A Both atoms contribute one electron each.
- B One atom contributes both electrons to the shared pair.
- C Electrons are transferred permanently between atoms.
- D Electrons are delocalized across a lattice of metal ions.
Correct answer: One atom contributes both electrons to the shared pair.
A coordinate covalent bond is a variation of a covalent bond where the shared pair of electrons comes from only one of the participating atoms. This is commonly seen in the formation of the ammonium ion ($NH_4^+$).
Which of the following molecules contains a triple covalent bond?
- A Oxygen ($O_2$)
- B Methane ($CH_4$)
- C Nitrogen ($N_2$)
- D Water ($H_2O$)
Correct answer: Nitrogen ($N_2$)
A nitrogen atom has five valence electrons and needs three more to complete its octet. Two nitrogen atoms share three pairs of electrons, forming a very strong triple bond ($N\equiv N$).
According to the VSEPR theory, what is the geometric shape of a methane ($CH_4$) molecule?
- A Linear
- B Trigonal planar
- C Tetrahedral
- D Bent
Correct answer: Tetrahedral
Methane has four bonding pairs of electrons and zero lone pairs around the central carbon atom. To minimize repulsion, these pairs orient themselves toward the corners of a tetrahedron, resulting in bond angles of 109.5°.
What is the primary reason why noble gases are generally unreactive?
- A They have high electronegativity.
- B They have a stable octet electron configuration.
- C They are found in the gaseous state at room temperature.
- D They have very small atomic radii.
Correct answer: They have a stable octet electron configuration.
Noble gases have a full valence shell (eight electrons, or two for Helium), which is a highly stable energetic state. Because they already have a stable octet, they have little tendency to gain, lose, or share electrons.
Which property is characteristic of most ionic compounds?
- A Low melting and boiling points
- B Conduct electricity in the solid state
- C High solubility in non-polar solvents
- D High melting points and brittleness
Correct answer: High melting points and brittleness
Ionic compounds form crystalline lattices held by strong electrostatic forces, requiring significant energy to break, hence high melting points. They are brittle because shifting the lattice aligns like-charged ions, causing them to repel and shatter.
The polarity of a covalent bond is determined by the difference in which property between the two atoms?
- A Atomic mass
- B Electronegativity
- C Ionization energy
- D Electron affinity
Correct answer: Electronegativity
Electronegativity is the ability of an atom to attract a shared pair of electrons. A significant difference in electronegativity between two bonded atoms results in an unequal sharing of electrons, creating a polar covalent bond.
Which of the following substances is held together by metallic bonding?
- A Sodium chloride
- B Diamond
- C Copper
- D Quartz
Correct answer: Copper
Metallic bonding consists of a lattice of positive metal ions surrounded by a 'sea' of delocalized valence electrons. This structure allows metals to be excellent conductors of electricity and heat.
In the Lewis structure of the water molecule ($H_2O$), how many lone pairs of electrons are on the central oxygen atom?
- A Zero
- B One
- C Two
- D Three
Correct answer: Two
Oxygen has six valence electrons; two are used to form single bonds with hydrogen atoms, leaving four electrons. These four electrons form two lone pairs, which contribute to the bent shape of the water molecule.
What is the bond angle in a molecule with a linear geometry, such as Carbon Dioxide ($CO_2$)?
- A 90°
- B 104.5°
- C 120°
- D 180°
Correct answer: 180°
In $CO_2$, the carbon atom forms two double bonds with oxygen atoms and has no lone pairs. The two bonding regions repel each other to opposite sides of the carbon atom, resulting in a 180° bond angle.
Which of the following is the strongest type of intermolecular force?
- A London forces
- B Dipole-dipole interactions
- C Hydrogen bonding
- D Dipole-induced dipole forces
Correct answer: Hydrogen bonding
Hydrogen bonding is a particularly strong type of dipole-dipole attraction that occurs when hydrogen is covalently bonded to highly electronegative atoms like N, O, or F. It is significantly stronger than standard dipole-dipole or dispersion forces.
What type of hybridization is found in the carbon atoms of ethene ($C_2H_4$)?
- A $sp$
- B $sp^2$
- C $sp^3$
- D $dsp^2$
Correct answer: $sp^2$
In ethene, each carbon atom is bonded to three other atoms (two hydrogens and one carbon) in a trigonal planar arrangement. This requires the mixing of one $s$ orbital and two $p$ orbitals to form three $sp^2$ hybrid orbitals.
Which molecule does NOT follow the octet rule?
- A Carbon tetrachloride ($CCl_4$)
- B Phosphorus pentachloride ($PCl_5$)
- C Nitrogen trifluoride ($NF_3$)
- D Dichlorodifluoromethane ($CCl_2F_2$)
Correct answer: Phosphorus pentachloride ($PCl_5$)
Phosphorus pentachloride is an example of an expanded octet. The central phosphorus atom is surrounded by ten valence electrons (five bonding pairs), which is possible for elements in the third period and beyond using $d$ orbitals.
What is the formal charge on the nitrogen atom in the ammonium ion ($NH_4^+$)?
- A -1
- B 0
- C +1
- D +2
Correct answer: +1
Formal charge is calculated as [Valence electrons] - [Non-bonding electrons] - [1/2 Bonding electrons]. For Nitrogen in $NH_4^+$, it is $5 - 0 - 4 = +1$.
Which bond is most polar among the following pairs?
- A C-H
- B N-H
- C O-H
- D F-H
Correct answer: F-H
Polarity increases with the difference in electronegativity. Since Fluorine is the most electronegative element in the periodic table, the F-H bond has the greatest difference and thus the highest polarity.
What characterizes a Sigma bond?
- A End-to-end overlap of orbitals along the internuclear axis
- B Sideways overlap of parallel $p$ orbitals
- C The presence of a nodal plane that contains the bond axis
- D Formation only within double and triple bonds, never single bonds
Correct answer: End-to-end overlap of orbitals along the internuclear axis
A sigma bond is the strongest type of covalent bond, formed by the head-on overlap of orbitals. The electron density is concentrated directly between the nuclei of the bonding atoms.
In a metallic lattice, what allows metals to be malleable and ductile?
- A Rigid directional covalent bonds holding the atoms in fixed positions
- B Strong electrostatic attraction fixing the ions in a rigid lattice
- C Brittle crystal planes that fracture under applied stress
- D Layers of metal ions sliding over one another in the electron sea
Correct answer: Layers of metal ions sliding over one another in the electron sea
Metallic bonds are non-directional. When a force is applied, the layers of metal cations can slide over one another while the delocalized electrons maintain the bond, preventing the metal from breaking.
Which of the following correctly describes a pi bond?
- A It is formed by the head-on overlap of two $s$ orbitals.
- B It is stronger than the sigma bond formed between the same atoms.
- C It allows free rotation of the atoms about the bond axis.
- D It is formed by the sideways overlap of parallel $p$ orbitals.
Correct answer: It is formed by the sideways overlap of parallel $p$ orbitals.
Pi bonds are formed by the lateral overlap of parallel $p$ orbitals. They are found in double and triple bonds and, unlike sigma bonds, they restrict the rotation of the atoms around the bond axis.
Lattice energy is a measure of the strength of which type of bond?
- A Ionic
- B Pi
- C Metallic
- D Hydrogen
Correct answer: Ionic
Lattice energy is the energy released when gaseous ions combine to form one mole of an ionic solid. It indicates the strength of the electrostatic attractions within the ionic crystal lattice.
Why does ice float on liquid water?
- A Ionic bonds between water molecules push them apart.
- B Covalent bonds in ice are longer than those in liquid water.
- C Solid water develops a metallic character that reduces its density.
- D Hydrogen bonding holds molecules in an open, cage-like lattice.
Correct answer: Hydrogen bonding holds molecules in an open, cage-like lattice.
In ice, each water molecule is hydrogen-bonded to four others in a fixed lattice. This arrangement keeps the molecules further apart than they are in the liquid state, making ice less dense than liquid water.