Reference Groups: A reference group is any group of people that individuals use as a standard for evaluating themselves and their own behavior (Schaefer). The term reference group was coined by Herbert Hymen in 1942 in a study of social class.
Fill in the orbitals according to the number of electrons in your atom. For instance, if we want to write an electron configuration for an uncharged calcium atom, we'll begin by finding its atomic number on the periodic table.
How to Write the Electron Configuration for Lithium. Lithium is the third element with a total of 3 electrons. In writing the electron configuration for lithium the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the remaining electron for Li goes in the 2s orbital. Therefore the Li electron configuration will be 1s22s1.