Free Chemical Bonding MCQs with Answers

• A. two sigma bonds
• B. two pi bonds
• C. one sigma bond formed by sp2 overlap and one pi bond formed by sideways overlap of unhybridised p orbitals
• D. one ionic and one covalent bond

Explanation: Each carbon uses three sp2 hybrids for sigma bonds to two hydrogens and to the other carbon, and the leftover p orbital on each overlaps…

• A. the sharing of a pair of electrons between two atoms
• B. the complete transfer of electrons from a metal to a non metal
• C. the overlap of two half filled orbitals
• D. the delocalisation of electrons over a lattice of cations

Explanation: Transfer produces oppositely charged ions held by electrostatic attraction, which is why ionic compounds have high melting points and…

• A. both shared electrons come from the same atom
• B. no electrons are shared
• C. it is much weaker than a normal covalent bond
• D. it involves the transfer of electrons

Explanation: One atom supplies the whole electron pair while the other provides an empty orbital, as when ammonia donates its lone pair to a hydrogen…

• A. sp3
• B. sp2
• C. sp
• D. unhybridised

Explanation: The carbon has only two regions of electron density, since each double bond counts as one region, so two sp hybrid orbitals point in…

• A. 90 degrees
• B. 109.5 degrees
• C. 120 degrees
• D. 180 degrees

Explanation: Four equivalent orbitals repel each other to the corners of a tetrahedron, which places them at 109.5 degrees.

• A. two sigma and two pi
• B. four sigma and no pi
• C. two sigma and four pi
• D. one sigma and three pi

Explanation: Each of the two carbon to oxygen double bonds contributes one sigma and one pi bond, giving two of each in total.

• A. it involves fewer electrons
• B. sideways overlap of p orbitals is less effective than head on overlap
• C. it is formed between different elements
• D. it has no electron density

Explanation: Sideways overlap concentrates less electron density between the nuclei than end on overlap does, so the pi bond is easier to break, which…

• A. linear
• B. trigonal planar
• C. tetrahedral
• D. bent

Explanation: Four regions of electron density spread as far apart as possible, which places them at the corners of a tetrahedron with angles of 109.5…

• A. tetrahedral
• B. octahedral
• C. trigonal bipyramidal
• D. square planar

Explanation: Six bond pairs around the central sulphur arrange themselves at 90 degrees to one another at the corners of an octahedron.

• A. single, double, triple
• B. triple, double, single
• C. double, single, triple
• D. all are equal

Explanation: More shared pairs pull the nuclei closer, so a triple bond is shorter than a double and a double shorter than a single, with carbon to…

• A. purely ionic
• B. polar covalent, with the shared pair drawn towards chlorine
• C. non polar covalent
• D. metallic

Explanation: Chlorine is more electronegative than hydrogen, so the shared electrons sit closer to it, giving chlorine a partial negative charge and…

• A. the carbon to chlorine bonds are non polar
• B. the four polar bonds are arranged symmetrically so their dipoles cancel
• C. chlorine and carbon have the same electronegativity
• D. the molecule is planar

Explanation: Each bond carries a substantial dipole, but the tetrahedral symmetry means the four vectors sum to zero, leaving the molecule non polar…

• A. HF
• B. HCl
• C. HBr
• D. HI

Explanation: Fluorine is the most electronegative element, so the difference from hydrogen is largest in hydrogen fluoride and the shared pair is most…

• A. sp3
• B. sp2
• C. sp
• D. a mixture of sp2 and sp3

Explanation: Each carbon forms three sigma bonds, two to neighbouring carbons and one to a hydrogen, using sp2 hybrids at 120 degrees, which makes the…

• A. the sharing of electrons between two adjacent atoms
• B. the attraction between a lattice of positive ions and a sea of delocalised electrons
• C. the transfer of electrons from one metal atom to another
• D. hydrogen bonding between metal atoms

Explanation: The valence electrons are free to move throughout the whole structure, which accounts for electrical and thermal conductivity, lustre and…

• A. zero
• B. one
• C. two
• D. three

Explanation: Oxygen has six valence electrons, two of which are used in bonding to the hydrogens, leaving two lone pairs.

• A. H2O
• B. NH3
• C. BeCl2
• D. CH4

Explanation: Beryllium in beryllium chloride has only two bond pairs and no lone pairs, so they point in opposite directions at 180 degrees.

• A. the bond length increases
• B. the bond length decreases and the bond order rises
• C. the atoms become larger
• D. the electronegativity difference falls to zero

Explanation: Shorter bonds hold the nuclei closer to the shared electrons, so more energy is needed to separate them, and each extra shared pair…

• A. the dative bond breaks immediately
• B. once formed, the origin of the electron pair no longer affects the bond
• C. nitrogen changes its hybridisation
• D. one hydrogen leaves the ion

Explanation: A bond is defined by the shared pair between the two nuclei, not by which atom supplied the electrons, so experimentally the four bonds…

• A. covalent bonds
• B. ionic bonds
• C. London dispersion forces
• D. hydrogen bonds

Explanation: Iodine molecules are non polar, so the only attraction available is the temporary induced dipole force, which nonetheless grows large…