Final answer:
The electron configuration of an atom describes the arrangement of electrons in its orbitals using orbital notation.
Step-by-step explanation:
The electron configuration of an atom describes the arrangement of electrons in its orbitals. It is represented using orbital notation, which consists of three pieces of information: the number of the principal quantum shell (n), the letter that designates the orbital type (subshell), and a superscript number that designates the number of electrons in that subshell.
For example, the electron configuration of lithium is 1s²2s¹, which means there are 2 electrons in the 1s orbital and 1 electron in the 2s orbital.