Question

What is the electron configuration of lithium, oxygen, nitrogen and potassium?

Answer 1

We know that each atom belonging to every single group and period has a characteristic electronic configuration. This electronic configuration of the elements determines their several properties. The electronic configuration also determines which element would combine with which other element and in what ratio.

Complete answer:
In order to deal with this question first we will elaborate the octet rule: The octet rule states that atoms are most stable when eight electrons occupy their valence shells. It is based on the fact that the atoms of the main group elements appear to be involved in chemical bonding in such a way that each atom of the resulting molecule has eight electrons in the shell of valence. The law of the octet applies only to the principal group elements. The halogens, oxygen, nitrogen, and carbon molecules are believed to follow the laws of the octet. The elements that follow this law usually include the s-block elements and the p-block elements except hydrogen, helium, and lithium. The number of electrons in the outermost shell of a given atom determines either its reactivity, or a propensity to form chemical bonds with other atoms. This outermost shell is known as the valence shell, and the electrons trapped inside are known as valence electrons. The electronic configuration is:
-Lithium: $1{{s}^{2}}~2{{s}^{1}}$
-Oxygen: $1{{s}^{2~}}2{{s}^{2}}~2{{p}^{4}}$
-Nitrogen: $1{{s}^{2}}~2{{s}^{2~}}2{{p}^{3}}$
-Potassium: $1{{s}^{2~}}2{{s}^{2~}}2{{p}^{6~}}3{{s}^{2}}3{{p}^{6~}}4{{s}^{1}}$
For Lithium there are two electrons in an s orbital; this means that it has two electrons in its $1s$ orbital: $1{{s}^{2}}$ it’s in the second period): $2{{s}^{1}}.$ For oxygen, it has four valence electrons in the $2p$ orbital series (because it’s in the second period): $2{{p}^{4}}.$ For Nitrogen, its electronic configuration is the exact same as oxygen, except with one less electron in the valence energy level. Oxygen’s electron configuration is $1{{s}^{2}}2{{s}^{2}}2{{p}^{4}}.$ one electron taken from that, it becomes $1{{s}^{2}}2{{s}^{2}}2{{p}^{3}}$ nitrogen. For potassium, it has one valence electron in the $4s$ orbital series (because it’s in the s block of the fourth period): $4{{s}^{1}}.$

Note:
Remember that the outermost shell of any element is the shell of Valence. Atoms in individual elements have various electrical properties, based on the atomic number of each element. The electrical arrangement refers to the distribution of electrons in various shells / orbits / levels of energy at each atom.