Final answer:
The electron configuration uses a specific notation including quantum shell number, orbital type, and number of electrons per subshell to describe the arrangement of electrons around an atom's nucleus, as seen in 1s¹ for hydrogen or 1s² 2s¹ for lithium. Abbreviated configurations can simplify complex electron arrangements by using noble gases as a reference point.
Step-by-step explanation:
The electron configuration of an atom describes the arrangement of electrons in its orbitals. This configuration is represented by a notation that includes the principal quantum shell number (n), the orbital type designated by a letter (l), and a superscript number indicating the number of electrons in that subshell. For instance, hydrogen has an electron configuration of 1s¹, meaning it has one electron in the 1s orbital, which is the closest to the nucleus.
For elements with more electrons, such as lithium, the configuration expands to include more subshells; the configuration for lithium is 1s² 2s¹. The sum of the superscript numbers equals the atomic number of the element, reflecting its total electron count.
An abbreviated electron configuration can be used for simplicity, which utilizes a noble gas to represent the core electrons and then adds on the configuration for the remaining valence electrons. Taking lithium again as an example, its abbreviated configuration would be [He] 2s¹.