In addition, we know that the neutrons and protons are what make up the nucleus which the electrons orbit. In chemistry, we want to be able to locate and characterize the electrons. To do this we must think about the electron in three dimensional space. Quantum numbers is a method that scientists use to describe the location of an electron. There are three quantum numbers, n, l m l , which represent each of the three dimensions.
All quantum numbers are always integers.
This value is the best estimate of the electrons distance from the nucleus. Below is a table of the first four subshells. The first three subshells are labeled according to the types of lines produced in the spectrum. After the fourth subshell, the labels procede in alphabetical order. The orbitals within a subshell are the same shape but different orientation.