Justin
Dunn
a and
Umesh Dewnarain
Ramnarain
*b
aUniversity of Johannesburg, Auckland Park, Gauteng, South Africa
bDepartment of Science and Technology Education, University of Johannesburg, Johannesburg 2006, South Africa. E-mail: uramnarain@uj.ac.za
First published on 11th September 2024
Continuous enhancement of mobile devices such as smartphones offers new opportunities for using these technologies in inquiry-based learning environments. Inquiry-based learning has followed deductive and inductive forms of inquiry, while the abductive form of inquiry that targets the development of higher-order thinking skills such as critical thinking is less prevalent. This study investigated the use of mobile technology in abductive-inquiry based teaching and learning of chemical bonding for grade 11 physical sciences learners in two South African schools. The study employed an explanatory sequential mixed-methods design that entailed first collecting quantitative data and then qualitative data to help explain or elaborate on the quantitative results. Two grade 11 physical sciences classes were randomly designated as the experimental and control groups in each of the two different schools. The experimental group in each school experienced activities in a laboratory using mobile technology-enhanced abductive scientific inquiry through the ‘Molecular Workbench’ web-based simulation using a mobile device, while the control group in each school experienced activities in abductive scientific inquiry in a science laboratory without using mobile learning technology. The principal findings indicated that learners within the control group displayed a significant increase in their performance to create a scientifically accurate hypothesis that is the essence of abductive inquiry, whereas for the experimental group there was no significant improvement in their hypothesis generation capacity. However, participants within the experimental group felt that their use of mobile devices created a sense of learner agency amongst themselves, developed their communication skills, made them feel responsible for their own learning, and also made learning scientific concepts more fun as opposed to what they are normally exposed to.
Abductive inquiry is a specific approach to inquiry-based learning that has the potential to develop higher-order thinking skills such as critical thinking (Raholm, 2010). Whereas in other forms of inquiry deductive and inductive processes are followed when learners use a known hypothesis to validate data or generate a rule, in abductive inquiry, the hypotheses are initially unknown (Ahmed and Parsons, 2013; Brandt and Timmermans, 2021). In abductive inquiry, the learner is exposed to scientific facts, theories, or principles, which are used as rules to formulate hypotheses on the observed phenomena. The learner makes meaning of the phenomenon by applying critical thinking skills to arrive at the hypothesis of the specific phenomenon observed (Oh, 2011).
This research investigated the use of mobile learning technologies in abductive inquiry-based learning. Continuous enhancement of mobile devices such as smartphones offers new opportunities for using these technologies in a classroom. As a result, mobile technologies such as tablets, iPads, smartphones, and laptops have become increasingly popular in K-12 classrooms (Zhang, 2015). The affordances of mobile technology include portability, data gathering, communication, and contextual and active learning (Parsons et al., 2016). Mobile technologies therefore hold much potential for supporting inquiry-based learning. In abductive inquiry-based learning, research conducted by Ahmed and Parsons (2013) has demonstrated that a mobile application, ‘ThinknLearn’, enhances learner performance, critical thinking skills and a deeper understanding of science content.
The abstractness and complexity of chemical bonding leads to various misconceptions amongst learners. Some widely documented misconceptions relate to the differences between ionic bonds and covalent bonds (Barke et al., 2009), the geometry of molecules (Uyulgan et al., 2014) and intra- and intermolecular forces (Vladušić et al., 2016). Oh (2022) maintains that abductive reasoning is well-suited to the construction of conceptual models that explain phenomena. This suggests that such reasoning in inquiry could support learners in conceptualising abstract phenomena such as chemical bonding. Furthermore, research by Engelschalt et al. (2023) showed the potential role of abductive reasoning in modeling for inquiry for explaining biological phenomena as complex systems. Despite the effectiveness of inquiry-based learning in addressing learner misconceptions (Mohd Radzi et al., 2017), there is a lack of exploration of mobile applications in facilitating science inquiry learning, particularly in abductive inquiry investigations. This study investigates the use of the ‘Molecular Workbench’ web-based simulation in abductive inquiry-based learning of chemical bonding. The research is guided by the following research question:
How can the use of mobile technology in abductive inquiry-based teaching and learning enhance the learning of chemical bonding by grade 11 physical sciences learners?
Abductive inquiry is a specific approach to inquiry-based learning that has the potential to develop higher-order thinking skills such as critical thinking (Raholm, 2010). Whereas in other forms of inquiry where deductive and inductive processes are followed when learners use a known hypothesis to validate data or generate a rule, in abductive inquiry, the hypotheses are initially unknown (Ahmed and Parsons, 2013). In abductive inquiry, the learner is exposed to scientific facts, theories, or principles, which are used as rules to formulate hypotheses on the observed phenomena. The learner makes meaning of the phenomenon by applying critical thinking skills to arrive at the hypothesis of the specific phenomenon observed (Oh, 2011).
The abductive inquiry model (AIM) is a specific model that can be adopted in classrooms when participating in abductive inquiry activities (Oh, 2011). The AIM comprises four essential elements, which are illustrated in the flowchart in Fig. 1 below.
![]() | ||
Fig. 1 Abductive inquiry model (adapted from Oh, 2011, p. 413). |
During the exploration phase, learners observe data of the phenomenon experienced and attempt to find a scientifically relevant way to explain the observed data. This is then followed by the examination phase, which consists of learners examining relevant scientific rules, which may enable them to provide a relevant explanation for the phenomenon under investigation. In the selection phase, learners reassess all previously formulated hypotheses and then select the one which based on scientific theory seems most plausible. In the case that learners find any flaws in this specific phase they may then revert back to any of the previous phases, namely the exploration or examination phase, to eradicate and replace this flaw or problem with a more refined explanation of the observed phenomenon (Ahmad, 2012). Hence, the first three phases of the AIM model are not linearly defined but are distinctly iterative in nature (Oh, 2011), where the hypotheses are repeatedly modified and then explained through a process of continuous development. Subsequently this results in the explanation being the final phase of this AIM model. In this phase, the learner elaborates on reasons for the specific phenomenon observed making use of the scientific rule and hypothesis selected by the learner in the previous phases of the model.
According to Johnson (2000), abduction forms part of the first phase of scientific inquiry as it leads to a deeper insight into the phenomenon that has been observed and can be correlated to existing theory to suggest possible new comprehension of the observed phenomenon. Subsequently, this new abducted insight can be interpreted and verified using deductive scientific inquiry to determine whether the new understanding may be accepted scientifically. Inductive scientific inquiry can then be used to determine if the new understanding is consistent with the existing scientific knowledge being taught in class (Raholm, 2010).
Moreover, to further elaborate on the relationship amongst the three different inquiry-based reasoning approaches, what follows is an example shown in Table 1 of the effect polarity has on the boiling points of alcohol and water at room temperature, and a description of how these three different inquiry-based reasoning approaches will consider the inquiry in terms of rule, case and result.
Deduction: | 1. Rule (condition or suggestion): alcohol is less polar than water. | 2. Case (hypothesis): a less polar substance has lower boiling points than polar substances. | 3. Result (observation): alcohol evaporates faster than water at room temperature. |
Induction: | 1. Case (hypothesis): a less polar substance has lower boiling points than polar substances. | 2. Result (observation): alcohol evaporates faster than water at room temperature. | 3. Rule (condition or suggestion): alcohol is less polar than water. |
Abduction: | 1. Rule (condition or suggestion): alcohol is less polar than water. | 2. Result (observation): alcohol evaporates faster than water at room temperature. | 3. Case (hypothesis): a less polar substance has a lower boiling point than polar substances. |
In addition to this, abductive inquiry when applied in the classroom has also been found to not only develop a learner's critical thinking capability through inference formation but to further develop scientific skills such as problem-solving (Ahmad, 2012; Ahmed and Parsons, 2013). Research on abductive inquiry such as that conducted by Ahmed and Parsons (2013) provides some insight into its ability to enhance learners’ understanding of abstract and complex scientific concepts through inference formation. At the time of conducting this research, limited (if any) research had been done on the effects of applying abductive inquiry into South African science classrooms. Furthermore, there is a lack of research worldwide on this topic. This invites further investigation into its possible role in enhancing learners’ understanding of a topic such as chemical bonding, which has proven to be a difficult concept to grasp for learners.
In light of the above, this study intended to determine the efficacy of mobile technology in teaching learners chemical bonding in an abductive inquiry-based learning environment in a South African schooling context. Accordingly, the following main research question was posed to drive the inquiry:
How can the use of mobile technology in abductive inquiry-based teaching and learning enhance the learning of chemical bonding by grade 11 physical sciences learners?
In addressing this question, the following objectives were set:
1. To compare the conceptual understandings of chemical bonding of the experimental and control groups upon experiencing abductive inquiry-based activities.
2. To compare the hypothesis generation competency of the experimental and control groups upon experiencing abductive inquiry-based activities.
3. To determine the perceptions of the experimental group learners and teachers on mobile technology-enhanced abductive inquiry-based learning.
Fig. 3 and 4 below depict phases of data collection for the experimental and control groups, respectively.
A diamond has a high melting point and high boiling point. This information suggests that the bonds in diamond are:
I. Weak | II. Strong |
Reason
A diamond is a covalent molecular solid.
B. A diamond is a macromolecule composed of covalently bonded atoms.
C. A diamond is a covalent network solid (continuous covalent lattice) composed of covalent bonded molecules.
D. A large amount of energy is required to break the intermolecular forces in the diamond.
Section B consisted of 3 open-ended hypothesis generating questions to explain their selected answer. They selected an appropriate interpretation of their answer from multiple options provided and they finally came up with their own hypothesis of the phenomenon observed based on the data they had collected from the experiments. Importantly, this explanation had to be based on existing scientific knowledge.
Here is an example of such an item:
Boiling point as measured | Circle possible intermolecular force present | Referring to boiling points provide a reason (hypothesis) for your answer | |
---|---|---|---|
Beaker A (water) | 100 °C | (A) Hydrogen bond | |
(B) Ionic bond | |||
(C) Dipole–dipole |
These hypothesis generating questions were marked as follows; ‘0’ for a wrong (or no) hypothesis; ‘0.5’ for a correct hypothesis but a wrong explanation to phenomenon observed; ‘1’ for a correct hypothesis with its explanation correct and relating to existing scientific knowledge. This made Section B questions add up to a total of 3 marks, subsequently making the grand total of the question paper to be out of 29 marks (26 marks from Section A, and 3 marks from Section B). The internal reliability of results was established by computing Cronbach's alpha (Tavakol and Dennick, 2011).
Lesson observations were conducted and recorded. This observation data from the experimental classes describes the use of mobile technology in enhancing abductive inquiry-based learning. After the experimental group of learners had experienced the activities, semi-structured focus group interviews were conducted with them to establish their perceptions of using the mobile application when doing abductive scientific inquiry. Three focus groups of 5 learners each were randomly drawn from each class. The interviews were recorded and later transcribed.
Two paired sample t-tests were conducted to compare pre- and post-test means for the control and experimental groups. An independent sample t-test was used to investigate the learning performance differences between the two groups in conceptual understanding of chemical bonding and hypothesis generation. The interview data were coded and classified, a process that involves reading through transcripts in order to have a comprehensive overview (Saldana, 2009). The codes emerged inductively from the data. After coding all the data, the codes sharing the same meaning were grouped together into sub-themes, and eventually these sub-themes were grouped together into themes (Saldana, 2009). Similarly, the lesson observation data was analyzed inductively to generate themes on learner engagement and teacher support during the activities. A codebook was developed and then shared with another researcher who applied the codebook in independently coding the interview data. Cohen's kappa was calculated to assess the inter-rater reliability in coding between the research and the second coder (Miles and Huberman, 1994).
The qualitative data analysis followed the codes-to-theory model as streamlined by Saldana (2015) in Fig. 5 below.
![]() | ||
Fig. 5 Codes-to-theory model for qualitative data analysis (Saldana, 2015, p. 14). |
In addition to this, an excerpt from the researcher developed codebook of how the interviews were analysed inductively following the above-mentioned analysis strategy is indicated in Table 2 below:
Codes | Code description | Excerpts from the interview | Category | Theme |
---|---|---|---|---|
“Physics was a challenge” | Describing the challenges learners faced prior to intervention | “physics was like, a challenge to me because my teacher had to explain it to me and I had to find other classmates to explain it to me, so I could understand much better” | Physics was a challenge | Learner agency |
Learner collaboration | Learners positive attitude towards learning through collaborating with their peers | “I find other classmates to explain it to me, so I could understand much better” | ||
“I could go ask for help from the teacher or the learner around me” | Learning through collaboration | |||
“You grasp it quicker” | Mobile technologies display information in such a summative matter, that it allows one to easily grasp knowledge and know what is expected of them. | “it gives you exact information and you grasp it quicker because you are on your phone when you forget then you are like oh let me go back and check again so it's quicker and easier to access than normal.” | Enhances learners retention and understanding. | |
“It helped me understand” | Learners find the mobile assisted abductive inquiry lessons aided their understanding of how chemicals bond | “It, it did quite help me understand how they bonded. They created a clear and yah, a clear picture of how, it, it's done compared to theory.” |
This study met the ethics requirements for human subjects research, and was approved by the Faculty of Education Research Ethics Committee at the authors’ university.
Groups | N | Min | Max | Mean | sd | df | t | p |
---|---|---|---|---|---|---|---|---|
Control group pre-test | 47 | 5 | 26 | 12.04 | 4.95614 | 46 | 2.333 | 0.588 |
Control group post-test | 47 | 4 | 21 | 14.34 | 4.20288 | |||
Experimental group pre-test | 48 | 6 | 24 | 13.67 | 4.37271 | 47 | 0.067 | 0.947 |
Experimental group post-test | 48 | 8 | 23 | 13.63 | 3.82392 |
As indicated in Table 3, the descriptive statistics indicate that the control group scored a pre-test mean score of 12.04 while the experimental group scored a pre-test mean score of 13.67, showing a mean score difference of 1.63 between the control and experimental group. This not being a major difference in pre-test mean score results, made the two groups comparable when investigating the effect of the intervention. The post-test results show that the control group increased in their conceptual understanding of chemical bonding, whilst the experimental group had a slight decrease in their conceptual understanding of chemical bonding. The increase for the control group learners had a pre-test-post-test mean difference of 2.3 while the experimental group showed a slight decrease of 0.04.
In order to determine if these changes in conceptual understanding were of any significance, two paired samples t-tests were conducted to compare pre- and post-test means for the experimental and control groups (see Table 3). The test showed that although there may have been an increase in performance for the control group (t(47) = 2.33, p > 0.05), this improvement proved not to be significant. Moreover, no significant improvement in performance for the experimental group was noticed (t(48) = 0.067, p > 0.05).
Research objective 2 that compared the hypothesis generation competency of the experimental and control groups upon experiencing abductive inquiry-based activities is addressed below.
Groups | N | Min | Max | Mean | sd | df | t | p |
---|---|---|---|---|---|---|---|---|
Control group pre-test | 47 | 0 | 3 | 0.85 | 1.08305 | 46 | 4.939 | 0.03 |
Control group post-test | 47 | 0 | 3 | 1.96 | 1.08262 | |||
Experimental group pre-test | 48 | 0 | 3 | 1.43 | 1.19318 | 47 | 0.260 | 0.796 |
Experimental group post-test | 48 | 0 | 3 | 1.46 | 1.10042 |
It is evident from the above table that although there was an improvement in the hypothesis generation capability of the experimental group, such an improvement was not significant t(47) = 0.260, (p > 0.05). However, there was a significant improvement in the control group's performance for this capability, t(46) = 4.939, (p < 0.05). This is indicative of control group learners having attained an increase in their ability to generate an accurate hypothesis, from an observed phenomenon.
In order to determine to what extent this insignificant increase was accurately spread throughout the sample population, the effect size of each sample recorded and analysed had to be measured. Cohen's d is a commonly accepted measure of the effect size a significant or insignificant increase might have on the entire population (Cohen, 1988). Hence, determining the effect size of this insignificant decrease in learners’ marks was obtained by calculating Cohen's d using this formula:
d = 1.03 |
Research objective 3 that determined the perceptions of the experimental group learners and teachers on mobile technology-enhanced abductive inquiry-based learning is addressed below.
Theme 1 Teacher and learner uncertainty in using mobile devices.
It was evident that both teachers and learners had limited experience in using mobile devices for science learning purposes. This is regarded as a factor that may have impacted the results for the experimental group learners. Contributing to this uncertainty was a lack of digital learning skills amongst learners. This is evident in the following interview excerpt.
I have terrible IT literacy ‘cause I never really did computers, growing up or in school we didn’t really do computers, if we did more of a uhm computer class from Grade one just teaching us the basic IT languages and foreign languages they may be, but, my IT skills and phone skills of technology, overall, I’m not very good at it.
The learners felt that their lack of digital knowledge hampered their opportunity to fully learn from the abductive inquiry activities. This was supported by both teachers who believed that a factor that could have hampered the experimental learner group's abductive inquiry experience was because of their lack of exposure to mobile devices due to their socio-economic circumstances. He expressed this view as follows:
The disadvantage is not all the learners have mobile phones, so it might disadvantage them. In terms of they might not know how to use it properly, others might not even have those phones in class.
Because now we’ve got disadvantaged schools, really, we’re still using chalkboards, so now it would take some time for those to be integrated, so we would need learners to have iPad for example.
Allied to learner uncertainly is the concern that due to learners having different skill sets, some would feel intimidated. This was highlighted below by a teacher:
Fear could hinder you know when you are not used to these things and doing practical in front of others. It's not easy, so because now one person had to be hands-on, and the others were just helping there so the person could have easily got intimidated by other fellow learners.
At the same time, the teachers also expressed uncertainty of their own digital skills. This is underlined below:
My knowledge is very limited to be honest and I still want to learn how can we use the technology of ICT to convey about learning?
Theme 2 Learners being distracted by mobile devices.
Mr Smith believed that learners were distracted by the devices and the unlimited WiFi that was made available to them. As a result, they were not focused on the task. This is reflected in the following interview excerpt:
Now what could have hindered them, is when they see Wi-Fi, they think that no, this is free data. Can I just check something else?”
This concern was also echoed by learners. For example, one learner stated this as follows:
The negative impact is that the learners might use it for other purposes as, such as like, uh playing games, WhatsApping, Instagram, social media and things like that, instead of using them to learn stuff like this.
However, while learner and teacher uncertainty, and learner distraction due to mobile devices are recognized as factors that impacted the results, there was also recognition of the potential of mobile devices as learning tools. Learner agency was one of the positives that emerged. A learner referred to this agency as follows:
It allows a child or a learner to be able to do it on their own.
Allied to agency, learners also appear to have more confidence in their learning due to the affordance allowed by mobile devices in accessing information from the website that was used. This is shown below:
In my opinion, the amount of information, I was shown on the website…. would… prepare me for a test… I would actually be able to apply the knowledge, that little knowledge, I got from that website…Uhm apply all those things that I’ve learnt and all those things that I’ve got from the website, I could possibly pass the test.
Research objective 1 sought to compare the conceptual understandings of chemical bonding of the experimental and control groups upon experiencing abductive inquiry-based activities. The results showed that the control group did not yield a significant increase in their conceptual understanding of chemical bonding; furthermore, the experimental group had a small decrease in their conceptual understanding of chemical bonding. This finding suggests that abductive inquiry alone does not support the conceptual understanding of chemical bonding, and the inclusion of mobile technologies has proven to have little to no effect on enhancing the conceptualisation of chemical bonding concepts. Although the literature abounds with the affordances of mobile learning technology for science learning, this finding is not unusual. For example, other studies show that there was no such difference in students’ learning performance with and without using a mobile device. The use of mobile devices during learning has been associated with cognitive distractions, reducing students' ability to focus on complex scientific concepts (Rosen et al., 2013).
Furthermore, multitasking, often facilitated by mobile devices, can lead to reduced comprehension (Wood et al., 2012). While there is compelling evidence for the use of mobile devices in the classroom, research on the use of mobile technology in education by Frohberg et al. (2009) that categorized 102 mobile-learning projects showed that mobile devices have been used primarily as a sort of reinforcement tool to stimulate motivation and strengthen engagement, and secondarily as a content-delivery tool. Few projects have used mobile devices to assist with constructive thinking or reflection. There is therefore a need for more research such as the current study to investigate the impact of mobile devices on higher-order cognitive outcomes.
However, when engaging the control group in abductive inquiry-based activities, a significant increase in overall learner conceptualisation was noted for this group in both schools (t(47) = 2.33, p < 0.05). This finding on the effect of abductive inquiry on conceptual understanding aligns well with a study conducted by Oh (2022), which concludes that abductive reasoning is well-suited to the construction of models that explain phenomena in earth sciences.
Research objective 2 compared the hypothesis generation competency of the experimental and control groups upon experiencing abductive inquiry-based activities. The findings from the study established that abductive scientific inquiry allowed learners to develop a more scientifically accurate hypothesis and explain scientific phenomena observed in hands-on science experiments done in class. The increase in scores for the experimental group was very small and not significant, however a significant increase in the control group accurate hypothesis generation was noted, with the mean score of hypothesis generation for the post-test (m = 1.96, s = 1.08) much higher than the mean score for the pre-test (m = 0.85, s = 1.08). The results obtained from a two-tailed paired samples t-test indicated a significant increase in learners’ accurate hypothesis generation capability within the control group (t(47) = 4.94, p < 0.05).
The findings in addressing research objective 3 on the perceptions of the experimental group in using these devices for abductive inquiry are now discussed. Interviews conducted with learners within the experimental group revealed that their readiness to use mobile devices to support abductive inquiry came across as a major limitation in hampering them from fully experiencing the benefits that abductive scientific inquiry may bring. This explained the insignificant improvement in scores of the experimental group in comparison to the control group's increase in performance of chemical bonding and hypothesis generation competency. The distracting nature of technology on learners’ academic conceptualisation of knowledge is also supported by the literature (Dontre, 2021). While both teachers and learners were of the view that although the inclusion of mobile devices in such a lesson makes learning more fun, saves time and gives learners a sense of responsibility for their own learning, learners first needed to be exposed and become more accustomed to using such devices for inquiry-based learning. Learners’ exposure to technology for the purposes of science learning is therefore an issue that will need to be addressed if such technology can be better exploited for learning gains. This is supported by other studies that found that aside from teacher development, learners need to be trained to use technology within a learning environment (Carstens et al., 2021).
Further studies could focus on the longitudinal effects of mobile technology in abductive inquiry, examining how long-term exposure and consistent use of devices impact learners' scientific reasoning and engagement.
Moreover, the inclusion of mobile devices in abductive inquiry appeared to not show a similar result. Learner readiness to engage in mobile technology-assisted abductive inquiry activities appeared to play a major role in the results obtained by the learners’ experimental groups. While studies in other countries show a high level of readiness to use mobile devices among science learners (e.g.Rahmat et al., 2023), more research is needed on the readiness of learners, especially in the African context where socio-economic factors are prevalent, to use mobile devices in science learning. Integrating mobile technology in science teaching, especially in the context of inquiry-based learning, can offer numerous benefits. However, ensuring that teachers are ready to effectively integrate mobile technology into their teaching practices is essential. There is a need for more targeted professional development of teachers that will address their needs to optimally utilise these technologies.
Directions: this test consists of two sections. Section A consists of 13 pairs of questions which examine your knowledge of chemical bonding. Each question has two parts: a multiple-choice answer followed by a multiple-choice reason. On the answer sheet provided, please circle one answer from both the answer and reason sections of each question.
Section B consists of a table that you must complete.
1. The most important particle in chemical bonding is:
I. Proton in the outer shell.
II. All electrons
III. Electron in the outer shell
Reason
A. The chemical bonding is due to the proton transfer
B. The chemical bonding is due to all electrons transfer
C. The chemical bonding is due to all electrons loss
D. The chemical bonding is due to the electron transfer in the outer shell
2. The state of electrons for an ionic bonding is:
I. Electron sharing | II. Electron transfer | III. Electron destroying |
Reason
A. Electrons of atoms will be shared with the same number of electrons.
B. Electrons of atoms will be entirely transferred to other atoms
C. Electrons of atoms will be entirely destroyed
D. Electrons of atoms will be entirely divided into other atoms
3. The state of ionic compounds at room temperature is:
I. Gas | II. Liquid | III. Solid |
Reason
A. Ionic compounds will have a strong lattice force
B. Ionic compounds will have a strong ionic bonding force
C. Ionic compounds will have a large size ion
D. Ionic compounds will have a large ionic charge
4. Sodium chloride, NaCl, exists as a molecule.
I. True | II. False |
Reason
A. The sodium atom shares a pair of electrons with the chlorine atom to form a simple molecule.
B. After donating its valence electron to the chlorine atom, the sodium ion forms a molecule with the chloride ion.
C. Sodium chloride exists as a lattice consisting of sodium ions and chloride ions.
D. Sodium chloride exists as a lattice consisting of covalently bonded sodium and chlorine atoms.
5. A diamond has a high melting point and high boiling point. This information suggests that the bonds in diamond are:
I. Weak | II. Strong |
Reason
A. A diamond is a covalent molecular solid.
B. A diamond is a macromolecule composed of covalently bonded atoms.
C. A diamond is a covalent network solid (continuous covalent lattice) composed of covalent bonded molecules.
D. A large amount of energy is required to break the intermolecular forces in the diamond.
6. Element C (electronic configuration 1S2 2S2 2p6 3S2 3p6 4S2) and element E (electronic configuration 1S2 2S2 2p5) react to form an ionic compound, CE
I. True | II. False |
Reason
A. An atom of C will share one pair of electrons with each atom of E to form a covalent molecule, CE2.
B. A macromolecule consists of covalently bonded atoms of C and E.
C. Atoms of C will each lose two electrons and twice as many atoms of E will each gain one electron to form an ionic compound CE2.
D. An atom of C will lose one electron to an atom of E to form an ionic compound CE
7. An atom of element A has two electrons in its outermost shell while an atom of element B has five electrons in its outermost shell. When A reacts with B, the compound will be:
I. Covalent | II. Ionic |
8. Water (H2O) and hydrogen sulfide (H2S) have similar chemical formula and structures. At room temperature, water is a liquid and hydrogen sulfide is a gas. This difference in state is due to:
I. Intermolecular forces between molecules
II. Intramolecular forces within molecules
Reason
A. The difference in the forces attracting water molecules and those attracting hydrogen sulfide molecules is due to the difference in the strength of the O–H and the S–H covalent bonds.
B. The bonds in hydrogen sulfide are easily broken whereas those in water are not.
C. The hydrogen sulfide molecules are closer to each other, leading to greater attraction between molecules.
D. The forces between water molecules are stronger than those between hydrogen sulfide molecules.
9. Which of the following best represents the position of the shared electron pair in the HF molecule
(I) H:F
(II) H:F
Reason
A. Non-bonding electrons influence the position of the bonding or shared electron pair.
B. As hydrogen and fluorine form a covalent bond, the electron pair must be centrally located.
C. Fluorine has a stronger attraction for the shared electron pair.
D. Fluorine is the larger of the two atoms and hence exerts greater control over the shared electron pair.
10. The density of water is maximum at the temperature of 4 °C.
I. True | II. False |
Reason
A. The mass of water is a maximum at the temperature of 4 °C.
B. The volume of water is maximum at the temperature of 4 °C.
C. The portion of hydrogen bonding of water is maximum at the temperature of 4 °C.
D. Mass and volume of water are maximum at the temperature of 4 °C.
11. The kind of bonding to make the water molecule (H2O) is:
I. Ionic bonding
II. Polar covalent bonding
III. Non-polar covalent bonding
Reason
A. Hydrogen loses an electron to be the hydrogen ion H+.
B. Oxygen gains two electrons to be the oxygen ion O2−.
C. Hydrogen and oxygen share electrons equally.
D. The electronegativity of oxygen is larger than that of hydrogen.
12. Iodine crystals I2(s) are soluble in ethanol CH3CH2OH(l)
(I) True
(II) False
A. Hydrogen bonds between ethanol molecules are much stronger than the dispersion forces between iodine molecules.
B. Hydrogen bonds between ethanol molecules and the covalent bonds between iodine molecules are of comparable strength.
C. Iodine molecules and the ethanol molecules are non-polar and “like dissolves like”.
D. London/dispersion forces between ethanol molecules and iodine molecules are of comparable strength and “like dissolves like”.
13. The strongest metallic bonding exists in:
I. Mercury | II. Sodium | III. Copper |
Reason
A. The state of metal is a liquid.
B. It is easy to be a (+) ion after losing electrons.
C. There are many free electrons moving between metal ions.
D. There exists a big charge in metal ions.
Section B: Complete the following table
Boiling point as measured | Circle possible intermolecular force present | Referring to boiling points provide a reason (hypothesis) for your answer | |
---|---|---|---|
Beaker A (water) | 100 °C | (D) Hydrogen bond | |
(E) Ionic bond | |||
(F) Dipole–dipole | |||
Beaker B (ethanol) | 64.7 °C | (A) Hydrogen bond | |
(B) Ionic bond | |||
(C) Dipole–dipole | |||
Beaker C (NaCl) | 1.413 °C | (A) Hydrogen bond | |
(B) Ionic bond | |||
(C) Dipole–dipole |
Question | Answer | Reason | |||||
Q1 | I | II | III | A | B | C | D |
Q2 | I | II | III | A | B | C | D |
Q3 | I | II | III | A | B | C | D |
Q4 | I | II | A | B | C | D | |
Q5 | I | II | A | B | C | D | |
Q6 | I | II | A | B | C | D | |
Q7 | I | II | A | B | C | D | |
Q8 | I | II | A | B | C | D | |
Q9 | I | II | A | B | C | D | |
Q10 | I | II | A | B | C | D | |
Q11 | I | II | III | A | B | C | D |
Q12 | I | II | A | B | C | D | |
Q13 | I | II | III | A | B | C | D |
Section B: Complete table
Boiling point as measured | Circle possible intermolecular force present | Referring to boiling points provide a reason (hypothesis) for your answer | |
---|---|---|---|
Beaker A (water) | 100 °C | (G) Hydrogen bond | |
(H) Ionic bond | |||
(I) Dipole–dipole | |||
Beaker B (ethanol) | 64.7 °C | (D) Hydrogen bond | |
(E) Ionic bond | |||
(F) Dipole–dipole | |||
Beaker C (NaCl) | 1.413 °C | (D) Hydrogen bond | |
(E) Ionic bond | |||
(F) Dipole–dipole |
This journal is © The Royal Society of Chemistry 2025 |