Structure of Atom
Atomic Orbital
An atomic orbital is a region around the nucleus where an electron is most likely to be found. It is a probability map, not a fixed path.
Electrons do not travel in neat circles. An orbital is described by a wave function (ψ), and its square (|ψ|²) gives the probability of finding the electron at each point. Where |ψ|² is large, the electron is likely to be.
Each orbital has a definite energy and shape (an s orbital is spherical, a p orbital is dumbbell shaped), and it holds at most two electrons, which must have opposite spins.
Where students slip up
The big misconception is picturing an orbital as an orbit, a fixed track the electron runs along like a planet. It is not a path at all. It is a cloud of probability. You can only say where the electron is likely to be, never exactly where it is or the route it takes.
Hold onto this
An orbital is a probability cloud, not a path. At most two electrons, opposite spins.
Why it helps in the exam: keep orbit and orbital apart: an orbit (Bohr) is a fixed circular path, an orbital is a probability region. Also remember s holds 2, p holds 6, d holds 10 electrons.
Where this connects
Because an orbital is a probability cloud with a definite shape, the shapes themselves explain the angles in molecules. The dumbbell p orbitals pointing along axes are the reason water bends and carbon builds tetrahedra.
Quick check
An atomic orbital is best described as:
- AA fixed circular path of an electron
- BA region where an electron is most likely to be found
- CThe nucleus of the atom
- DA type of chemical bond