Free Chemical Bonding MCQs with Answers

• A. Covalent bond
• B. Ionic bond
• C. Metallic bond
• D. Hydrogen bond

Explanation: Sodium transfers its single valence electron to chlorine, producing Na⁺ and Cl⁻ ions held together by electrostatic attraction — an ionic…

• A. the mutual repulsion of the electron pairs around the central atom, which arrange themselves as far apart as possible
• B. the masses of the atoms attached
• C. the number of neutrons in the central atom
• D. the temperature at which the molecule is examined

Explanation: Bonding and lone pairs are regions of negative charge, so they repel and settle into the arrangement of minimum repulsion, which fixes the…

• A. trigonal planar
• B. pyramidal, with a bond angle of about 107 degrees
• C. tetrahedral, with an angle of 109.5 degrees
• D. linear

Explanation: Nitrogen has three bond pairs and one lone pair, so the four electron regions point tetrahedrally but only the three bonded atoms are…

• A. oxygen is more electronegative than hydrogen
• B. water molecules are hydrogen bonded
• C. the two lone pairs on oxygen repel the bond pairs more strongly than bond pairs repel each other
• D. the molecule is linear

Explanation: Oxygen has four electron regions, two bonding and two lone pairs, so the basic arrangement is tetrahedral, but the two lone pairs squeeze…

• A. pyramidal
• B. bent
• C. tetrahedral
• D. trigonal planar with bond angles of 120 degrees

Explanation: Boron forms three bonds and has no lone pair, so the three electron regions lie flat at 120 degrees, and the molecule is an exception to…

• A. sideways overlap of two p orbitals
• B. head on overlap of two orbitals along the axis joining the nuclei
• C. the transfer of electrons from one atom to another
• D. attraction between two ions

Explanation: End on overlap concentrates electron density directly between the nuclei, which makes a sigma bond stronger than a pi bond and allows free…

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

Explanation: The two carbon to hydrogen bonds are sigma, and the carbon to carbon triple bond consists of one sigma plus two pi bonds, giving three…

• A. the sigma bond is too strong
• B. the atoms are too heavy
• C. turning one carbon would break the sideways overlap of the pi bond
• D. double bonds are ionic

Explanation: The pi bond depends on two parallel p orbitals overlapping sideways, and rotating one carbon by ninety degrees would destroy that overlap…

• A. sp
• B. sp2
• C. sp3
• D. sp3d

Explanation: One 2s and three 2p orbitals mix to give four equivalent sp3 hybrids directed to the corners of a tetrahedron, which explains why all four…

• A. 25 per cent
• B. 33.3 per cent
• C. 50 per cent
• D. 100 per cent

Explanation: An sp2 hybrid is formed from one s and two p orbitals, so the s contribution is one in three.

• A. sp3, with the lone pair occupying one of the four hybrid orbitals
• B. sp2
• C. sp
• D. unhybridised

Explanation: Nitrogen has four regions of electron density, three bonds and one lone pair, so four sp3 hybrids are needed even though only three of…

• A. has an even number of atoms
• B. contains at least one lone pair
• C. the individual bond dipoles do not cancel because of the molecular shape
• D. contains hydrogen

Explanation: Carbon dioxide has two strongly polar bonds but is linear, so the two dipoles point in opposite directions and cancel, leaving a non polar…

• A. H2O
• B. NH3
• C. HCl
• D. CCl4

Explanation: Tetrachloromethane has four polar carbon to chlorine bonds arranged symmetrically about the central carbon, so the four dipoles cancel…

• A. debye units
• B. joules
• C. angstroms
• D. moles

Explanation: Dipole moment is the product of the magnitude of the separated charge and the distance between the centres of charge, and it is quoted in…

• A. the two atoms become more similar
• B. the electronegativity difference between the two atoms increases
• C. the bond becomes shorter
• D. the temperature rises

Explanation: The greater the electronegativity difference, the more unequally the pair is shared, until at a difference of roughly 1.7 the bond is…

• A. released when a bond is formed between two ions
• B. required to melt one mole of a covalent solid
• C. required to break one mole of a particular bond in the gaseous state
• D. stored in the nucleus of an atom

Explanation: Because bond breaking is always endothermic, bond energy values are positive, and the same amount is released when the bond re-forms.

• A. single greater than double greater than triple
• B. all three are equal
• C. double greater than triple greater than single
• D. triple greater than double greater than single

Explanation: More shared pairs mean a greater attraction between the nuclei and the bonding electrons, so the triple bond is the strongest and also the…

• A. the energy released in forming new bonds exceeds the energy absorbed in breaking old ones
• B. the energy absorbed in breaking bonds exceeds the energy released in forming them
• C. no bonds are broken
• D. the products are gases

Explanation: Breaking bonds always costs energy and forming them always releases it, so the sign of the overall enthalpy change is decided by which…

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

Explanation: Methane has four bond pairs and no lone pairs, so it is tetrahedral, while the carbon in carbon dioxide has only two regions of electron…

• A. the central atoms become larger in that order
• B. the number of lone pairs on the central atom increases from zero to one to two
• C. the bonds become more ionic
• D. the molecules become heavier

Explanation: Each additional lone pair exerts stronger repulsion than a bond pair, squeezing the remaining bonds closer together, so the angle falls by…