Orbits and orbitals (2006)

Orbits and orbitals (2006)(chemguide.co.uk)

33 points by joegreen 7 years ago | 7 comments

jgamman 7 years ago |

One useful way to think of each year of chem/science study is to assume _it's the last year this student will take the subject_. From that perspective, the student will spend the rest of their life with _this_ mental model.

When viewed like this a mental model of a nucleus with electrons 'orbiting' around it is entirely valid and literally drops the student in the early 20th century.

One of the problems with experts is that they try building a straight line from zero to expert that never needs a backtrack step.

Personally I like the opportunity for students to learn about the experimental evidence that _forces them_ to need a better theory than the one they've come in with. Cognitive dissonance is one of the most powerful forces students have for learning - a good teacher should be engineering these moments as part of their lesson design.

blackholesRhot 7 years ago |

These concepts make more sense after one has been exposed to quantum mechanics. One of the first things you do in an intro to quantum mechanics class is calculate the energy levels of a Hydrogen atom (and then Helium.) Chemistry is literally applied quantum mechanics; and everything in quantum mechanics is probabilistic. A more accurate picture of an orbital is that it’s an energy level where a cloud of probability mass lives that corresponds to, if one were to take a photograph of the atom, the likelihood of finding an electron in any given location (wave function collapse.) But before a measurement, the electron really was a cloud of probability mass.

throwawaymath 7 years ago | |

Many things become more intuitive after you've been exposed to quantum mechanics, but that's trading one learning curve for another one (and a significantly steeper, albeit more generalizable one). If you already have familiarity with quantum mechanics then what you're explaining is useful. But if you don't, it's probably not a practical or efficient use of time to work through elementary QM first :)

mhh__ 7 years ago | |

Chemguide is aimed at A-level students, e.g. 17 year olds: Doing the math is out of the question, sadly.

acqq 7 years ago | | |

But even before 17 I‘ve learnt with the orbitals diagrams like here:

https://chem.libretexts.org/Bookshelves/Physical_and_Theoret...

Which I still find more informative than the drawings on the original post page.

michaelsbradley 7 years ago |

How might one conceive of orbitals with respect to the De Broglie–Bohm theory[+]?

[+] https://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory

michaelsbradley 7 years ago | |

Found this, The Hydrogen atom in Bohmian Quantum Theory[+]

  If the Bohmian interpretation of quantum mechanics is considered in
  the case of the hydrogen atom, it leads to a prediction that "normal"
  quantum mechanics does not make. That is the existence of a distance of
  closest approach of the electron to the proton. This distance of two
  hundred fermi is of the order of the Planck length, a region where the
  "normal" laws of physics are thought to break down. If the probability
  density of finding an electron inside this region could be experimentally
  measured, that would thus be a definite test to differentiate between the
  two interpretations of quantum mechanics.

[+] https://www.academia.edu/483415/The_Hydrogen_atom_in_Bohmian...

If the Bohmian interpretation of quantum mechanics is considered in the case of the hydrogen atom, it leads to a prediction that "normal" quantum mechanics does not make. That is the existence of a distance of closest approach of the electron to the proton. This distance of two hundred fermi is of the order of the Planck length, a region where the "normal" laws of physics are thought to break down. If the probability density of finding an electron inside this region could be experimentally measured, that would thus be a definite test to differentiate between the two interpretations of quantum mechanics.