What is meant by an atomic energy level? Give two differences between an atomic orbit, as described by Bohr, and an atomic orbital - Leaving Cert Chemistry - Question b - 2019

1. An atomic orbit, as described by Bohr, is a defined pathway where an electron travels in a circular fashion around the nucleus, whereas an atomic orbital is a probability distribution that represents the regions in space where an electron is likely to be found.

2. The Bohr orbit is two-dimensional and has a fixed distance from the nucleus, while an atomic orbital is three-dimensional and has no fixed distance from the nucleus, allowing for various shapes and sizes.

A p orbital is a specific region of space where electrons are likely to be found. In contrast, a p sub-level consists of three p orbitals that are oriented differently along the x, y, and z axes. The p orbital has a dumbbell shape, while the p sub-level comprises these three orbitals, collectively allowing for different orientations.

(insert diagram of p orbital and p subshell here)

The electron configuration for a nickel atom (atomic number 28) in its ground state is:

$1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8$

One piece of evidence supporting the existence of atomic energy levels is the emission spectrum observed when atoms are energized. When an electron transitions between energy levels, it emits or absorbs photons at specific frequencies, creating distinct spectral lines that correspond to these energy levels.