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Chemistry Grade 11 Unit 2: CHEMICAL BONDING

115 national exam questions have come from this unit. It runs 80 pages; one careful study pass takes about 8.0 hours, and its difficulty is moderate among Chemistry units. Each section below lists the questions set from it, with the year, and opens the page that teaches it.

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2.1 Introduction · read p. 67
Not asked in a national paper yet.
2.1.2 Types of Chemical Bonding · read p. 67
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2.1.1 The Octet Rule · read p. 68
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2.2 Ionic Bonds · read p. 69
Not asked in a national paper yet.
2.2.1 Lewis Electron-Dot Symbols · read p. 69
Not asked in a national paper yet.
2.2.2 Formation of Ionic Bonds · read p. 69
  • 2018 E.C., Q17 – Which of the following statements is CORRECT regarding the formation of ionic compounds?
  • 2017 E.C., Q46 – A student carried out an experiment to determine the melting points of $\mathrm{NaCl}$ and $\mathrm{CuCl_2}$. He/she added 0.2 g of $\mathrm{NaCl}$ and $\mathrm{CuCl_2}$ into two different test tubes and heated both tube
  • 2015 E.C., Q56 – Given the following: bond energies (kJ/mol) H-H 936 N-N 193 N=N 409 N≡N 942 and the enthalpy for the reaction 1 2 N 2 ( g ) + 3 2 H 2 ( g ) → NH 3 ( g ) ; ΔH = -45 kJ/mol What is the bond energy for NH ? 3
  • 2015 E.C., Q19 – The energy required to completely separate one mole of a solid ionic compound into gaseous ions is a/an
  • 2013 E.C., Q61 – According to the transition state theory
  • 2012 E.C., Q72 – For lithium, enthalpy of sublimation = +161 kJ/mol, first IE = +520 kJ/mol. Dissociation energy of F2 = +154 kJ/mol, electron affinity of F = -328 kJ/mol. Lattice energy of LiF = -1047 kJ/mol. The overall enthalpy of for
  • 2011 E.C., Q41 – Based on the information given in the table below, what is the enthalpy change for the reaction: $2\,\mathrm{H_2O_2(g)} + \mathrm{S(s)} \rightarrow \mathrm{SO_2(g)} + 2\,\mathrm{H_2O(g)}$ A table with two columns and fou
  • 2010 E.C., Q29 – What will be the charges on the ions formed when silicon reacts with nitrogen?
  • 2009 E.C., Q66 – Based on the following information (KJ) -286 414 -425 What will be the standard enthalpy changes for the reaction? ?
  • 2007 E.C., Q47 – The enthalpies of formation of gaseous $\mathrm{N_2O}$ and $\mathrm{NO}$ at 298K are 82 and 90KJ/mol, respectively. The enthalpy change for the reaction $\mathrm{N_2O(g) + \frac{1}{2}O_2(g) \rightarrow 2NO(g)}$ is
  • 2007 E.C., Q21 – Which of the following ionic compounds has the greatest lattice energy?
  • 2006 E.C., Q22 – Which compound contains both covalent and ionic bonds?
  • 2005 E.C., Q40 – How many kilo joules of heat are absorbed when 20 g of NaCl(s) is decomposed in to Na(s) and (g) at constant pressure according to the following reaction? 2Na(s) + Cl (g) →2NaCl(s) ΔH = 2 −821.8 kl
2.2.3 Exceptions to the Octet Rule in Ionic Compounds · read p. 69
Not asked in a national paper yet.
2.2.4 Properties of Ionic Compounds · read p. 83
Not asked in a national paper yet.
2.3 Covalent Bonds and Molecular Geometry · read p. 83
  • 2018 E.C., Q19 – Which of the following lists correctly shows the strength of the intermolecular attractive forces in decreasing order?
  • 2016 E.C., Q7 – A student collected four beakers in his/her laboratory and added some small amounts of the following: naphthalene to the first, graphite to the second, iodine to the third and alcohol to the fourth. If they added equal v
  • 2016 E.C., Q14 – Which of the following descriptions of the property of a covalent compound is CORRECT?
  • 2015 E.C., Q16 – How many non-bonding pairs of electrons are present in the valence shell of the central atom in $\mathrm{ClF_3}$?
  • 2013 E.C., Q16 – Which of the following is an example of exception to the octet rule?
  • 2013 E.C., Q31 – Covalent compounds are liquids or gases at room temperature and have statements low melting and boiling points. Which of the following statements explains these properties of covalent compounds?
  • 2012 E.C., Q23 – Which of the following is a Lewis acid but not a Brønsted acid?
  • 2011 E.C., Q73 – Which of the following molecules has the largest dipole moment?
  • 2010 E.C., Q3 – When a student draws a plausible Lewis structure for hydrazine molecule ( ), how many lone pair of electrons are available?
  • 2010 E.C., Q25 – The number of resonance structures for are:
  • 2009 E.C., Q37 – Which one of the following is a Lewis acid?
  • 2008 E.C., Q37 – How many bonding pairs and lone pairs, respectively does the ion have?
  • 2007 E.C., Q34 – How many unpaired electrons are there in the Lewis structure of a ion?
  • 2005 E.C., Q23 – The total number of electrons participating in the bond formation of carbonate anion, in the molecule of carbonic acid are:
2.3.1 Molecular Geometry · read p. 100
  • 2018 E.C., Q21 – You want to design a set of molecules whose central atoms all exhibit sp² hybridization. Using the concept of molecular geometry and hybridization, which of the following groups of molecules could best satisfy this requi
  • 2018 E.C., Q22 – The molecule BF₃ consists of a boron atom bonded to three fluorine atoms. Based on VSEPR theory what is the shape and bond angle of BF₃?
  • 2017 E.C., Q56 – The molecule of BF has both bonding and lone pair of electrons. Based upon these electrons, which one is the 3 CORRECT molecular geometry of the molecule of BF ? 3
  • 2017 E.C., Q72 – Consider the molecular structure of COCl shown below. What are the predicted bond angles Cl-C-O and Cl-C- 2 Cl?
  • 2016 E.C., Q71 – A water molecule has two bond pairs and two lone pairs of electrons. Which of the following is CORRECT about these pairs of electrons?
  • 2016 E.C., Q16 – The hybridization of the central atom xenon (Xe) in xenon tetraflouride, XeF 4 , is sp 3 d 2 . Which of the following is the shape of XeF 4 ?
  • 2015 E.C., Q46 – Which statement describes valence shell electron pair repulsion (VSEPR) theory?
  • 2015 E.C., Q18 – Which one of the following statements is CORRECT?
  • 2015 E.C., Q15 – Which one of the following is the main reason for the large difference in dipole-moment between the triatomic molecules water (H₂O) and carbon dioxide (CO₂)?
  • 2013 E.C., Q32 – Both carbonyl sulphide, COS (SCO), S=C=O and carbon dioxide (CO 2 ) O=C=O are linear molecules. COS is polar whereas CO 2 is non-polar. This is because
  • 2012 E.C., Q51 – Which one of the following species has the same molecular geometry: CO2, H2O, BeCl2, and N2O?
  • 2012 E.C., Q71 – A neutral molecule having the general formula AX3 has one unshared pair of electrons on A. Which is the hybridization of A?
  • 2012 E.C., Q13 – Based on the Valence shell electron pair repulsion (VSEPR) theory which of the following would have a tetrahedral arrangement of electrons around the central atom?
  • 2012 E.C., Q58 – Which one is the correct order of increasing Cl-A-Cl bond angle in the following species where A is central atom: I. BCl3, II. SiCl4, III. SCl2, IV. PCl3?
  • 2012 E.C., Q73 – Which of the following statements is correct about hydrogen cyanide (HCN)?
  • 2011 E.C., Q47 – What is the molecular shape of $\mathrm{ICl_4^-}$?
  • 2011 E.C., Q22 – There is a progressive decrease in the bond angle in the series of molecules CCl₄, PCl₃, and H₂O. According to the VSEPR model, this is best explained by:
  • 2011 E.C., Q56 – Which of the following statements is correct about nitrosyl chloride (NOCl)?
  • 2010 E.C., Q58 – Given the following species, , , , , . What is the correct order of F - A - F bond angles? 2 < 2 BeF < 2 NF < 3 BF < 3 CF4 BeF < 2 OF < 2 NF < 3 BF < 3 CF
  • 2008 E.C., Q41 – Which of the following molecules does not have a trigonal bipyramidal electron-pair geometry?
  • 2008 E.C., Q38 – Which of the following molecule does not have a tetrahedral central atom?
  • 2008 E.C., Q39 – The x, y and z carbon labels named in the stem are not visible anywhere in the rendered picture.]
  • 2008 E.C., Q40 – Antimony (Sb) is a group v element, what will be the molecular geometry and number of lone pair electrons, respectively that exists in the ion $[\mathrm{SbCl_5}]^{2-}$?
  • 2007 E.C., Q41 – The molecular geometry of ion is
  • 2006 E.C., Q25 – Which molecule or ion does NOT have a tetrahedral shape?
  • 2005 E.C., Q62 – Which of the following molecules has a dipole moment?
2.3.2 Intermolecular Forces in Covalent Compounds · read p. 107
  • 2018 E.C., Q7 – A student misunderstood that London dispersion forces are insignificant and can be ignored when predicting physical properties. Which of the following is the best to evaluate this claim?
  • 2018 E.C., Q29 – Which statement best explains why alcohols generally have higher boiling points than alkanes with similar molecular mass?
  • 2017 E.C., Q13 – Which statement below CORRECTLY describes dipole-dipole forces? It is the force that exists
  • 2017 E.C., Q42 – Which of the following organic compounds has the highest boiling point?
  • 2017 E.C., Q47 – What is the cause of unusual high boiling points of $\mathrm{HF}$, $\mathrm{H_2O}$ and $\mathrm{NH_3}$?
  • 2017 E.C., Q14 – Comparing the forces between molecules of similar molar masses, which one of the following produces the weakest force?
  • 2017 E.C., Q71 – Which statement below CORRECTLY expresses hydrogen bonding? It is formed by bonding
  • 2016 E.C., Q15 – The attractive force between molecules is known as _________.
  • 2016 E.C., Q31 – Which of the following is responsible for the unusual high boiling points of HF, H 2 O and NH 3 ?
  • 2015 E.C., Q59 – Which one of the following explains dipole-dipole force?
  • 2014 E.C., Q44 – How is hydrogen bonding formed? It is formed when a hydrogen atom is bonded to
  • 2013 E.C., Q15 – Hydrogen bonding occurs in compounds that contain H-N, H-O and H-F bonds. These bonds are stronger than the ordinary dipole-dipole interactions because
  • 2012 E.C., Q17 – Oxygen, nitrogen and fluorine bond with hydrogen to form molecules. These molecules are attracted to each other by
  • 2011 E.C., Q9 – Which of the following compounds does NOT contain both ionic and covalent bond?
  • 2009 E.C., Q2 – The force that hold different atoms or ions together are called?
  • 2008 E.C., Q7 – Which of the following is not a form of chemical bonding?
  • 2006 E.C., Q60 – When the following substances are arranged in order of increasing melting point (lowest melting point first), the correct order is:
2.4 Metallic Bonding · read p. 111
Not asked in a national paper yet.
2.4.1 Formation of Metallic Bonding · read p. 111
Not asked in a national paper yet.
2.4.2 Electron-Sea Model · read p. 112
Not asked in a national paper yet.
2.4.3 Properties of Metals and Bonding · read p. 112
  • 2018 E.C., Q18 – Why is graphite a good conductor of electricity, while diamond (C) is not, even though both are forms of carbon allotropes?
  • 2015 E.C., Q58 – In order to illustrate the structure and properties of a solid, a student put hundred marble balls in to a box that representing metal cations and the empty space between and around the marble representing the electron s
  • 2012 E.C., Q15 – Which of the following solid substances contains positive ions immersed in a sea of mobile electrons?
  • 2006 E.C., Q26 – Why are metals soft and malleable?
2.5 Chemical Bonding Theories · read p. 115
Not asked in a national paper yet.
2.5.1 Valence Bond (VB) Theory · read p. 115
  • 2018 E.C., Q20 – When two chlorine atoms combine to form a chlorine molecule (Cl₂), a covalent bond is formed due to the overlapping of atomic orbitals. Which orbital overlap is responsible for the formation of the bond in Cl₂?
  • 2014 E.C., Q28 – In which of the following molecules is the central atom sp 2 hybridized?
  • 2013 E.C., Q33 – Which of the following statements is true about the formation of CH4 according to valence bond theory?
  • 2013 E.C., Q34 – Phosphorus (Z=15) has the electronic configuration 1s²2s²2p⁶3s²3p³, what kind of hybridization does phosphorus undergo in the formation of phosphorus pentachloride (PCl5)?
  • 2012 E.C., Q52 – Which hybridization change does the carbon atom undergo in the combustion of methane? CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)
  • 2012 E.C., Q54 – Which one of the following characteristics applies to PCl3? I. Nonpolar molecule II. Polar bonds III. Trigonal- pyramidal molecular geometry IV. sp^2 hybridized
  • 2012 E.C., Q70 – Which of the following hydride orbital is favoring the formation of see-saw?
  • 2012 E.C., Q32 – Which one of the following best describes the formation of pi (π) bond?
  • 2011 E.C., Q48 – What hybridization change, if any, occurs at the underlined atom in the following reaction: $\underline{\mathrm{C}}\mathrm{O_2}+\mathrm{H_2O}\to\mathrm{H_2CO_3}$
  • 2010 E.C., Q59 – How many electrons are present in the $\sigma_{2p}$ molecular orbital of $\mathrm{N_2^+}$?
  • 2010 E.C., Q26 – In the following equation, what type of hybridization change, if any occurs at the Xe atom? sp d 3 sp d 3 2 dsp2 sp3
  • 2010 E.C., Q24 – What is (are) the bond angle (s) in $\mathrm{SF_6}$?
  • 2009 E.C., Q32 – What kind of hybrid orbitals are utilized by the carbon atom in $\mathrm{CF_4}$ molecules?
  • 2008 E.C., Q43 – Formic acid, which is released by ants, has a molecular formula of $\mathrm{HCOOH}$. What are the possible hybridizations that exist in the molecule?
  • 2008 E.C., Q42 – How many atomic orbitals are required for an hybridization?
  • 2008 E.C., Q50 – Which of the following is not true about carbonyl compounds?
  • 2007 E.C., Q1 – According to valence bond theory. Which orbitals on bromine atoms overlap in the formation of the bond in ?
  • 2007 E.C., Q15 – How many sigma and Pi bonds are present in the following molecule? $\mathrm{H_3C-CH=CH-CH_3}$
  • 2007 E.C., Q49 – The hybridization of the central atom in the $\mathrm{XeF_4}$ molecule is
  • 2007 E.C., Q20 – What hybridization change does the carbon atom undergo in the combustion of methane? CH (g) + 2O (g) →CO (g) + 2H O (g) 4 2 2 2 → 2 2 → 3
  • 2006 E.C., Q29 – How many bonds are present in ?
  • 2005 E.C., Q58 – Which of the following hybrid orbitals is favouring the formation of trigonal bipyramidal?
  • 2005 E.C., Q21 – Which of the following molecules has a trigonal bi pyramidal structure?
2.5.2 Molecular Orbital Theory (MOT) · read p. 131
  • 2017 E.C., Q6 – What is the electron configuration of molecule as per the molecular orbital model? (Atomic number of )
  • 2015 E.C., Q8 – Which one of the following resulted from interaction of the atomic orbitals of bonding atoms to produce new electron distribution associated with the entire molecule?
  • 2014 E.C., Q27 – Which of the following belongs to chemical bonding theories?
  • 2012 E.C., Q14 – When the 1s-orbitals of two hydrogen atoms combine to form a hydrogen molecule, then which molecular orbitals are formed?
  • 2012 E.C., Q55 – According to molecular orbital theory, which one of the following species is most likely to exist?
  • 2012 E.C., Q56 – According to molecular orbital theory, what is the bond order of O2?
  • 2010 E.C., Q34 – Which of the following orbital diagrams is correct for the carbide ion( )? σ σ σ σ π 1s 2 1s ∗2 2s 2 2s ∗2 2p 4 σ σ σ σ π σ π 1s 2 1s ∗2 2s 2 2s ∗2 2p 4 2p 2 2p ∗2
  • 2009 E.C., Q31 – What is the bond order of a superoxide anion, with the chemical formula ?
  • 2008 E.C., Q34 – What would happen to the oxygen molecule upon ionization to ?
  • 2006 E.C., Q58 – Based on molecular orbital theory, the bond orders of $\mathrm{H_2}$, $\mathrm{H_2^+}$ and $\mathrm{H_2^-}$ are, respectively.
  • 2005 E.C., Q59 – Which one of the following molecules/molecular ions is paramagnetic according to the molecular orbital theory?
2.6 Types of Crystal · read p. 135
  • 2015 E.C., Q38 – Which one of the following is an example of molecular crystals?
  • 2013 E.C., Q18 – Which of the following pair is true about the general properties of the different types of crystalline solids Type of solid Hardness Melting point Conduction of heat and electricity I. Ionic Hard High Good II. Covalent H
  • 2012 E.C., Q34 – Which types of solid materials are typically hard, have high melting points and poor electrical conductivities? I. Ionic II. Metallic III. Covalent-network
  • 2005 E.C., Q24 – Which of the following crystals possess high electrical and thermal conductivities?