MDCAT Chemistry · Chemistry · Atomic structure. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.
The wave model does not give the electron a fixed path. It gives an orbital: a region of space where the electron is most likely to be found. Each orbital holds at most two electrons.
Four quantum numbers describe an electron. Three of them (n, l and m) come from Schrödinger's wave equation and describe the orbital. The fourth, the spin quantum number s, describes the electron itself.
An s orbital is a sphere, and a 2s orbital is larger than a 1s orbital. A p orbital has a dumb-bell shape, and each shell from n = 2 has three of them at right angles. Electrons fill the orbitals of lowest energy first.
Students pair up p or d electrons too early when counting unpaired electrons. Put one electron in each orbital of the subshell first, then start pairing.
Answer: 4 unpaired electrons
Type what you are stuck on. The helper finds the explanation, worked examples and the notes to read, free and instant.
← Particles, photons and the Bohr modelGas laws →Take a MDCAT Chemistry test