The Quantum Model and Electron Configurations

Name: The Quantum Model and Electron Configurations
Author: StemPy Lab

Bohr's circles work for hydrogen, and they fail for every other atom. The better picture is a cloud of probability. In this course we meet the waves of matter, the uncertainty principle, the four quantum numbers and the shapes of orbitals. Then we use three rules to write the electron configuration of any atom, and we explain the odd cases, such as chromium and copper.

4 lessons, about 1 h 45 min4 simulations12 problems8 practice questionsPython in every lesson

Created by StemPy Lab

Course outline (4 lessons)

Lesson 1about 25 min
Waves of matter and the uncertainty principle
Every moving particle has a wavelength, $\lambda = \frac{h}{mv}$ . We see it only for very small particles such as electrons. Heisenberg showed that the position and the momentum of such a particle cannot both be known exactly: $\Delta x \,\Delta p$ is at least $\frac{h}{4\pi}$ . So an electron has no fixed path, only a probability of being found.
1 simulation2 practice questions1 Python program4 problems1 Python lab
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Lesson 2about 25 min
Orbitals and the four quantum numbers
In the quantum model, the electron is described by a wave function, and its square gives the probability. An orbital is such a wave function, where the electron is found with high probability. Each orbital has three quantum numbers: $n$ , $l$ and $m_l$ . The electron has a fourth, the spin $m_s$ .
1 simulation2 practice questions1 Python program3 problems
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Lesson 3about 30 min
Shapes and energies of orbitals
An s orbital is a sphere, a p orbital has two lobes along an axis (three orientations), and a d orbital usually has four lobes (five orientations). In hydrogen the energy depends on n only. In an atom with more electrons it also depends on l: ns is below np, below nd, below nf, and the orbitals fill in the order of increasing n + l.
1 simulation2 practice questions1 Python program2 problems
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Lesson 4about 25 min
Filling the orbitals: electron configurations
Electrons fill the orbitals by three rules. The Aufbau principle fills the lowest energy first. Pauli's exclusion principle allows at most two electrons in an orbital, with opposite spins. Hund's rule puts one electron in each orbital of a subshell before any pair. Chromium and copper are exceptions, because half-filled and full d subshells are extra stable.
1 simulation2 practice questions1 Python program3 problems1 Python lab1 question set1 note
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Quantum Model: Challenge Paper

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The Quantum Model and Electron Configurations

Course outline (4 lessons)

Waves of matter and the uncertainty principle

Orbitals and the four quantum numbers

Shapes and energies of orbitals

Filling the orbitals: electron configurations

Test Your Learning

Your teacher

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