- What two physical properties of molecules did van der Waals add to correct the gas equation?
Chemical Bonding and Molecular Structure
How atoms bond and molecules are shaped.
- How did Werner deduce three-dimensional molecular structures without any instrument capable of seeing them directly?
- What method did Willstätter use to work out the structure of chlorophyll without modern spectroscopy?
- What experimental steps let Willstätter's team identify chlorophyll's porphyrin ring and central magnesium ion using only 1910s chemistry?
- What is the shared electron pair, and why did Gilbert Lewis consider it the foundation of covalent bonding?
- Why did Lewis wait roughly fourteen years between sketching the cubical atom model and publishing his 1916 paper?
- How did Irving Langmuir extend Lewis's shared-pair idea into a broader theory of electron shells and valence?
- What everyday chemistry concepts, like the octet rule and Lewis dot structures, descend directly from this model?
- What was Gilbert Lewis's 1916 proposal about atoms sharing electron pairs, and how did Langmuir build on it in 1919?
- How does the concept of covalence differ from the ionic model of one atom donating electrons to another?
- Why did Irving Langmuir win the Nobel Prize in Chemistry in 1932 while Gilbert Lewis, who originated the shared-electron idea, never did?
- Why were the tools available before X-ray crystallography so blunt for working out cholesterol's molecular structure?
- Why does a tiny fraction of light change wavelength when it passes through a transparent material?
- Why did it take Fischer nearly two decades to work out haemin's structure?
- What is a dipole moment, and how does it reveal the shape of a molecule?
- How did Peter Debye use X-ray and electron diffraction to determine molecular architecture?
- Why is the unit of dipole measurement named the debye?
- How did Debye's methods change physical chemistry from a discipline of recipes into one of geometry?
- How did Linus Pauling combine quantum mechanics with X-ray crystallography to explain why atoms bond in the shapes they do?
- What is electronegativity, and why was making it a measurable quantity such a significant advance?
- What problem does resonance theory solve for molecules that don't fit a single structural formula?
- How does X-ray crystallography work backwards from a diffraction pattern to a molecule's three-dimensional structure?
- How does molecular orbital theory differ from the older valence-bond picture of chemical bonding?
- What chemical phenomena, like the colour of organic dyes or the stability of aromatic rings, could molecular orbital theory explain that older models could not?
- Where did the chemistry term 'orbital' come from, and who coined it?
- Why did it take until 1966 for Mulliken's 1920s and 1930s work on molecular orbitals to be recognised with a Nobel Prize?
- Why does conformational analysis matter for designing drugs?
- How did Gerhard Herzberg use spectroscopy to determine the geometry and electronic structure of short-lived molecules?
- Why did the sandwich-compound bonding model have no real precedent in organic chemistry at the time?
- Why did borane molecules like diborane seem to violate conventional chemical bonding rules?
- What geometric structure explains why a sixty-carbon cluster is unusually stable?
- Why did the researchers propose a soccer-ball-shaped cage of hexagons and pentagons for C60, and why did they name it after Buckminster Fuller?
- Why do metallic bonds resist forming flat, stable monolayers the way graphene's carbon bonds do?