0% HL - Models of Bonding & Structure 25 MCQ from 2025 Question Bank Models of Bonding & Structure (all topics) DP IB HL Chemistry Quiz 1 / 25 1. Which of the following statements correctly describes what happens when magnesium fluoride is formed? A. One magnesium atom gains two electrons to achieve a full outer shell of electrons B. For every magnesium ion formed, two fluorine atoms each gain one electron to form two fluoride ions, each with a single negative charge C. Two fluorine atoms each gain one electron, to form a fluorine molecule where each atom has a full outer shell D. Electrons are transferred from the fluorine atoms to the magnesium atoms B Explanation: Magnesium has two electrons in its outermost shell and loses both to achieve a full outer shell (Mg^2+). Fluorine has seven electrons in its outermost shell; it needs one more electron to achieve a full outer shell (F^1−). Two fluorine atoms are therefore required for each magnesium atom in order to form a neutral ionic compound (where the charges of the positive and negative ions cancel out). 2 / 25 2. Which of the following is NOT true of metals? A. Metals tend to have higher ionization energies than nonmetals across the same period B. Metals have a small number of electrons in their valence energy level C. Metals are found on the left side of the periodic table D. Metals tend to form cations in ionic bonding A Explanation: Across the same period, metals have lower ionization energies than non-metals due to lower nuclear charges with the same number of shells (shielding effect). 3 / 25 3. Which of the following has covalent bonding? I. CCl4 II. Ca3N2 III. NH3 A. III only B. I and II only C. I and III only D. I, II and III C Explanation: Non-metal elements bond to each other covalently. Ca3N2 is made up of a metal and a nonmetal (with a large difference in electronegativity) and has ionic bonding. 4 / 25 4. Which of the following characteristics of transition metals results in high electrical conductivity? A. Large atomic radius B. Strong ionic bonds C. High relative atomic mass D. Delocalized electrons in unfilled d-orbitals D Explanation: To successfully answer this question, the student must recall that electrical conductivity requires freely moving electrons. Metals are able to conduct electricity because the valence electrons are able to move freely through the lattice in the sea of delocalized electrons. The size and mass of the atom do not factor into the ability of the material to conduct electricity. While transition metal salts can conduct electricity, the ability to form ionic bonds does not explain conductivity. This question is categorized as easy because it only involves the recall of basic information about metals and conductivity. 5 / 25 5. Based on their structures, which of the substances below is likely to be the most volatile? A. HF B. HCl C. H2SO4 D. HNO3 B Explanation: The other three in theory, can form hydrogen bonds due to O−H and F−H bonds present 6 / 25 6. Which shows the oxygen-to-oxygen bonds in order of increasing average bond enthalpy? A. O≡O<O=O<O−O B. O−O<O≡O<O=O C. O=O<O−O<O≡O D. O−O<O=O<O≡O D Explanation: Triple bonds are stronger than double bonds which are in turn stronger than single bonds. The greater the number of shared pairs of electrons, the stronger the bond and the greater the bond enthalpy. 7 / 25 7. Which is a correct description of the bonding present in the following allotropes of carbon? Graphene Diamond Graphite A. 3-dimensional material with bond angles of 109.5° 2-dimensional material with bond angles of 120° Hexagonal layers with bond angles of 120° B. Hexagonal layers with bond angles of 120° 3-dimensional material with bond angles of 109.5° 2-dimensional material with bond angles of 120° C. 2-dimensional material with bond angles of 120° 3-dimensional material with bond angles of 109.5° Hexagonal layers with bond angles of 120° D. 2-dimensional material with bond angles of 120° Hexagonal layers with bond angles of 120° 3-dimensional material with bond angles of 109.5° A. A B. B C. C D. D C Explanation: Graphite is made up of individual graphene layers. Both have carbon atoms with three electron domains and trigonal planar shapes. Each carbon atom in diamond has four electron domains resulting in tetrahedral arrangements. 8 / 25 8. Which of the following is the correct order for % ionic character from highest to lowest for the following compounds? A. SiO2 , MgO , ZnO , Li2O B. Li2O , MgO , ZnO , SiO2 C. SiO2, ZnO, MgO, Li2O D. ZnO, MgO, Li2O, SiO2 9 / 25 9. Which compounds have an ionic lattice in the solid state? I. Ammonium sulfate II. Hydrogen chloride III. Sodium carbonate A. I and II only B. I and III only C. II and III only D. I, II and III B Explanation: Ionic bonds form between oppositely charged ions; NH^4+ and SO4^2− in ammonium sulfate and Na+ and CO32−Na+ in sodium carbonate. Due to a smaller difference in electronegativity and both being nonmetals, H−Cl bonds are polar covalent. 10 / 25 10. Which molecule would be considered polar covalent? A. CO2 B. NH3 C. CH4 D. SO3 B Explanation: The bonds between N and H are polar due to the difference in electronegativity. The overall shape of the NH3 is asymmetrical (trigonal pyramidal), resulting in a molecule with a net dipole moment. CO2 and SO3 both have polar bonds, but the molecules are symmetrical. Therefore, they do not have net dipole moment. The C-H bonds are not polar due to a small difference in electronegativity. 11 / 25 11. Sodium fluoride contains ionic bonding. Which statement correctly describes ionic bonding? A. The electrostatic attraction between positive ions, arranged in a lattice, and delocalized electrons B. A force of attraction that operates between molecules in a lattice C. The electrostatic attraction between oppositely charged ions D. The electrostatic attraction between a shared pair of electrons and positively charged nuclei C Explanation: Oppositely charged ions attract, it is an ionic bonding; Choice A describes metallic bonding; Choice B describes a simple molecular lattice; Choice D describes a covalent bond. 12 / 25 12. Which of the following statements regarding silicon dioxide, SiO2, are correct? I. The structure is described as a giant covalent structure with a tetrahedral arrangement II. The structure is insoluble in water and has a high melting point III. The structure has a pair of nonbonding electrons present on the silicon atoms A. I, and II only B. I and III only C. II and III only D. I only A Explanation: SiO2 has a giant covalent structure where each Si atom is singly bonded to four oxygen atoms (while maintaining a Si ratio of 1:2). As there are four electron domains around each silicon atom, the structure has a tetrahedral arrangement. SiO2 is held together by strong covalent bonds requiring a large amount of energy to overcome, resulting in a high melting point. The strong bonds, together with the fact that there are no charged particles present, lead to insolubility in polar solvents such as water. 13 / 25 13. Carbon tetrachloride has covalent bonding. Which of the following clearly describes this type of bonding? A. The electrostatic force of attraction by oppositely charged ions B. The force of attraction between the electron donor and electron acceptor C. The intermolecular force between hydrogen and most electronegative elements D. The electrostatic force of attraction between the shared pairs of electrons and the positively charged nuclei D Explanation: Choice A refers to ionic bonding; Choice B could refer to ionic bonding or specifically coordinate (dative) bonding; Choice C refers to hydrogen bonding. 14 / 25 14. Which statement explains the high boiling point of NH3? A. Strong London forces B. Strong N−H covalent bonds C. Strong hydrogen bonds D. Strong dipole-dipole interactions C Explanation: NH3 has all of the bonds/forces named above, but its high boiling point is due to the presence of hydrogen bonds which are the strongest intermolecular forces. Hydrogen bonding is possible due to the presence of N−H bonds. 15 / 25 15. Covalent bonds result from the overlap of atomic orbitals. Which of the following atomic orbitals would overlap to produce a σσ bond in the orientation shown? A. B. C. D. A. A B. B C. C D. D B Explanation: A σ bonding orbital is produced by end-to-end (direct) overlap of atomic orbitals. Students should be familiar with orbital overlap diagrams of this type, as they are covered extensively in the course. The question is therefore categorized as easy. 16 / 25 16. CH3COOH has which of the following intermolecular forces? I. London II. Dipole-Dipole III. Hydrogen bonds A. I only B. I and III only C. I, II, and III D. II only C Explanation: Carboxylic acids have hydrogen bonding due to O−H bonds. 17 / 25 17. What is the formula of the compound formed between lithium and nitrogen? A. LiN3 B. LiN2 C. Li2N3 D. Li3N D Explanation: Lithium is in group 1 and so forms Li^+ ions. The formula of the nitride ion is N^3−as nitrogen is in group 15. For the positive and negative charges to cancel out, three Li^+ ions are needed for each N^3− ion. 18 / 25 18. Which of the following cannot conduct electricity in a molten state? I. PCl3 II. NaCl III. SO2 A. I and II only B. II and III only C. I, II and III D. I and III only D Explanation: Simple molecular covalent structures cannot conduct electricity due to an absence of charged particles. NaCl is an ionic compound that has ions that are free to move when in a molten state. 19 / 25 19. Which of the following is the correct formula for strontium sulfide? A. Sr2S2 B. SrS2 C. SrS D. Sr2S C Explanation: Strontium is in group 2 and so forms Sr^2+ ions. The formula of the sulfide ion is S^2− as sulfur is in group 16. For the positive and negative charges to cancel out, one of each ion is required. 20 / 25 20. In which instance is ionic bonding most likely to occur? A. When two metals are chemically combined B. When a non-metal in group 17 reacts with a non-metal from a different group C. When a metal and a non-metal react with one another D. When a noble gas reacts with the most reactive element in group 1 C Explanation: Metals and non-metals have the greatest differences in electronegativity and so ionic bonds are formed. 21 / 25 21. Ethene has the following structural formula: Which orbitals of the carbon atoms are used to form the C−H and C=C bonds of ethene? C−H bonds C=C bond A. sp^2 orbitals p orbitals B. p orbitals sp^2 and p orbitals C. sp^2 orbitals sp^2 and p orbitals D. p orbitals sp^2 orbitals A. A B. B C. C D. D C Explanation: The sp^2 orbitals in ethene are used to form σ bonds, while the non-hybridized p orbitals overlap laterally to form the C−C π bonds. The C=C bond contains one σ and one π bond, so it involves both sp^2 and p orbitals. This question is moderately difficult as the student must recognize the difference between sp^2 and p orbitals and understand how they contribute to both σ and π bonds without the aid of orbital diagrams. 22 / 25 22. Which correctly states the relative size of the bond angles for H2O, NH3, and CH4? A. CH4< NH3< H2O B. H2O<NH3<CH4 C. H2O<CH4<NH3 D. CH4<NH3<H2O B Explanation: All three central atoms (N, C, and O) have four electron domains. An increasing number of lone pairs reduces the angle between the bonding pairs. In CH4 there are no lone pairs and it has a tetrahedral shape with bond angles of 109.5°. In NH3 there is one lone pair and it has a trigonal pyramidal shape with bond angles of 107°. In H2O, there are two lone pairs, and it has a bent shape with bond angles of 104.5°. 23 / 25 23. The molecule O2 contains one σσ and one π bond. How do pp orbitals in the O atoms overlap to produce the π bond? A. End-to-end overlap results in high electron density along the bond axis B. Sideways overlap results in high electron density along the bond axis C. End-to-end overlap results in high electron density above and below the bond axis D. Sideways overlap results in high electron density above and below the bond axis D Explanation: The student must recall the appearance of a π bond and the way in which it is formed. This information is stated clearly in the syllabus, so the question is categorized as easy. Option A describes the formation of a σ bond. 24 / 25 24. Which of the following substances is the most soluble in water, with the correct reason given? Substance Reason A. PF3 The bonds are very polar B. PF3 The molecule has a permanent dipole C. NH3 It can form hydrogen bonds with itself D. NH3 It can form hydrogen bonds with water molecules A. A B. B C. C D. D D Explanation: All statements are correct, but only D is a reason for solubility in water 25 / 25 25. Which of the below gives the intermolecular forces in water in the correct order from weakest to strongest? A. London<dipole-dipole<hydrogen bonding B. Dipole-dipole<London<hydrogen bonding C. Hydrogen bonding<dipole-dipole<London D. London<hydrogen bonding<dipole-dipole A Explanation: Recall that hydrogen bonds are the strongest intermolecular forces, and London forces are the weakest. Your score is 0% Restart quiz Send feedback
