Chemical Bonding 1: Basic Concepts

Chemical Bonding I: Basic Concepts examines general ideas of chemical bonding between atoms and ions and how this bonding affects the chemical properties of the elements. An overview of Lewis symbols, Lewis structures and the octet rule is presented including the role of valence electrons in ionic and covalent bonding. The energy changes that accompany ionic bond formation are also discussed with emphasis on lattice energy. The chapter covers guidelines and general procedures for writing Lewis structures or electron dot formulas for molecular compounds and polyatomic ions. The concepts and applications of resonance, formal charge and exceptions to the octet rules are presented, along with coverage of the relationship between bond polarity and electronegativity.

The Periodic Table needs negative orbitals in order to eliminate quantum weirdness: a new quantum chemistry mathematics

A consensus among quantum experts is that the quantum world is not properly understood. It is a mistake to think we can cure quantum weirdness by tinkering with superficial aspects of quantum mechanics (QM). We propose that nature uses (–ψ) as its wave function, whereas QM uses (+ψ). We propose therefore that the Periodical Table should be changed to negative orbitals (–ψ). Surprisingly, this change makes almost no difference to chemistry on a practical level. The Born rule takes the absolute square of an amplitude to obtain a probability to test in chemistry lab P=|–ψ|2=|+ψ|2. We propose a new math based on (–ψ) that is the mirror image of quantum mathematics. We call it the Theory of Elementary Waves (TEW). The negative sign is not an electrical charge. It has nothing to do with Coulomb’s law. Valence electrons are unchanged. Ions, covalent bonds, dipoles, metals, hydrogen bonding and the hydrogen 21 cm line are unchanged. The octet rule and rules for drawing dot structures of molecules do not change. Amino acids, sugars and DNA do not change their handedness. We cite abundant experimental evidence showing that TEW is correct and QM is wrong.

JUMPm: A Tool for Large-Scale Identification of Metabolites in Untargeted Metabolomics

Metabolomics is increasingly important for biomedical research, but large-scale metabolite identification in untargeted metabolomics is still challenging. Here, we present Jumbo Mass spectrometry-based Program of Metabolomics (JUMPm) software, a streamlined software tool for identifying potential metabolite formulas and structures in mass spectrometry. During database search, the false discovery rate is evaluated by a target-decoy strategy, where the decoys are produced by breaking the octet rule of chemistry. We illustrated the utility of JUMPm by detecting metabolite formulas and structures from liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) analyses of unlabeled and stable-isotope labeled yeast samples. We also benchmarked the performance of JUMPm by analyzing a mixed sample from a commercially available metabolite library in both hydrophilic and hydrophobic LC-MS/MS. These analyses confirm that metabolite identification can be significantly improved by estimating the element composition in formulas using stable isotope labeling, or by introducing LC retention time during a spectral library search, which are incorporated into JUMPm functions. Finally, we compared the performance of JUMPm and two commonly used programs, Compound Discoverer 3.1 and MZmine 2, with respect to putative metabolite identifications. Our results indicate that JUMPm is an effective tool for metabolite identification of both unlabeled and labeled data in untargeted metabolomics.

Chemical bonding in cuprous complexes with simple nitriles: octet rule and resonance concepts versus quantitative charge-redistribution analysis

Resonance structures for six cuprous complexes with simple nitriles are interpreted by means of a quantitative analysis of charge redistribution upon copper-nitrile bonding.

The challenges of learning and teaching chemical bonding at different school levels using electrostatic interactions instead of the octet rule as a teaching model

Teaching chemical bonding using the octet rule as an explanatory principle is problematic in many ways. The aim of this case study is to understand the learning and teaching of chemical bonding using a research-informed teaching model in which chemical bonding is introduced as an electrostatic phenomenon. The study posed two main questions: (i) how does a student's understanding of chemical bonding evolve from lower- to upper-secondary school when an electrostatic model of chemical bonding was used at the lower-secondary level? (ii) How does the teaching of octets/full shells at the upper-secondary level affect students’ understanding? The same students were interviewed after lower-secondary school and again during their first year at upper-secondary school. Their upper-level chemistry teachers were also interviewed. The interview data were analysed using the grounded theory method. The findings showed that the students’ earlier proper understanding of the electrostatic-interactions model at the lower-secondary level did not prevent the later development of less-canonical thinking. Teachers’ pedagogical content knowledge (PCK) of the explanatory principles of chemical bonding and how to use explanations in science education needs to be promoted in both pre-service teacher education and during in-service training.

A perspective on quantum mechanics and chemical concepts in describing noncovalent interactions

Since quantum mechanical calculations do not typically lend themselves to chemical interpretation, analyses of bonding interactions depend largely upon models (the octet rule, resonance theory, charge transfer, etc.). This sometimes leads to a blurring of the distinction between mathematical modelling and physical reality.

Structural and electronic properties of defects at grain boundaries in CuInSe2

Octet rule violation near the grain boundary plane is common in Σ3 grain boundaries, with important structural and electronic implications.

What Are the Structures of the Octet Rule Obeying All-Carbon Species Cx (2 ≤ x ≤ 7 and Larger x)?

With most carbon structures still unknown and undiscovered, it becomes increasingly important to find a way to discover, characterize, and understand them. This paper discusses the possible structures for all-carbon species in which each carbon obeys the octet rule. The number and structural diversity of such compounds strongly increases with the number of carbons: C2, 1; C3, 1; C4, 3; C5, 6; C6, 15. Only some of the C7 species were drawn -- merely 23 isomers were given. To guarantee structural uniqueness, names and visual inspection appear to be insufficient. Instead, a new method, using the eigenvalues and eigenvectors of the structure's adjacency matrix and modified matrices, was introduced and then employed. With this we hoped to gain a better understanding of what was chemically reasonable and realizable for our produced structures.