Write full electron configurations and indicate the valence electrons and the core electrons for each element.
Here, we are going to write the electronic configurations of the given elements and also indicate the number of valence and core electrons.
The distribution of electrons in different orbitals is known as electronic configuration of the atom.
In writing the electronic configuration, an orbital is shown by using its proper symbol.The number of electrons present in an orbital is shown as the right-hand superscript of the symbol of the orbital.
For example, the electronic configuration of hydrogen is 1s1. This means that the single electron in hydrogen occupies the s orbital present in the principal energy level n = 1. Similarly the electronic configuration of other elements are written.