How Many Valence Electrons Does Nitrogen (N) Have? [Valency of Nitrogen]

Nitrogen, a chemical element with the symbol Si and atomic number 14, is a colorless liquid, gas, or solid. At normal temperature and pressure, two atoms of nitrogen bind together to form colorless and odorless dinitrogen (N2) gas. N2 forms about 78% of the earth’s atmosphere which makes it the most abundant uncombined element on the earth's surface.

In chemical laboratory, dinitrogen can be prepared by treating an aqueous solution of ammonium chloride and sodium nitrite.

NH₄Cl + NaNO₂ → N₂ + NaCl + 2 H₂O

You are here to know valence electrons of the nitrogen atom, aren’t you? Don’t worry along with nitrogen valence electrons we will explain its valency also. But before that let’s have some basic ideas about what these two terms are:

Difference Between Valence Electrons and Valency

Valence electrons are the total number of electrons present in the outermost shell of an atom (i.e. in outermost orbital). The valence electrons for a neutral atom are always definite, it cannot be varied (more or less) in any condition for a particular atom and may or may not be equal to its valency.

Valency is defined as the total number of electrons an atom can lose, gain, or share at the time of bond formation to get a stable electronic configuration i.e. to complete an octet. The valency of an atom can be variable in different compounds or chemical reactions due to the different bonding circumstances. Most of the time valency varies/changes due to change in oxidation and reduction states.

Nitrogen (N) Valence Electrons

There are four simple steps to find out the valence electrons for nitrogen atom which are:

Step 1: Find the Atomic Number

To find out the atomic number of nitrogen, we can use the periodic table. With the help of the periodic table, we can easily see that the atomic number of nitrogen is 7. As its atomic number is 7, it has 7 protons, and for neutral nitrogen, the number of protons is always equal to the number of electrons i.e. has 7 electrons in its nucleus.

Step 2: Write Electron Configuration

Electron configuration is the arrangement of electrons on the orbitals. The nitrogen atom has a total of 7 electrons so, we have to put 7 electrons in orbitals. The electrons will be placed in different orbitals according to the energy level: [1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f]. Now,

Nitrogen electron configuration N (7) =  1s²2s²2p³ (complete configuration).

= [He] 2s²2p³  (condensed configuration).

Step 3: Determine Valence Shell

As we know, the valence shell of an atom can be found from the highest number of principle quantum numbers which are expressed in the term of n, and in [He]2s²2p³, the highest value of n is 2 so that the valence shell of nitrogen is 2s²2p³.

Step 4: Find Valence Electrons

The total number of electrons present in the valence shell of an atom are called valence electrons, and there are a total of five electrons present in the valence shell of nitrogen (2s²2p³). Thus, nitrogen has five valence electrons.

Valency of Nitrogen (N)

There are many different ways to find out the valency of an atom which reflects the ability of an atom to bond with other atoms. Valence describes how easily an atom or a free radical can combine with other chemical species. The valency of an atom is determined based on the number of electrons lost, gained, or shared with another atom at the time of bond formation.

An atom is said to be stable when its outermost shells have eight electrons (except H & He). If the total number of electrons in outermost shells is between one to four, the atom has positive valency and if electrons are between four to eight, the valency is calculated by subtracting from eight and valency will be zero. Atoms having four outermost electrons possess both positive and negative valency, and atoms having eight outermost electrons, valency will be zero (i.e. noble gases).

Elements like nitrogen can reach the stable state (nearest inert gas configuration [Ne]) by getting 3 electrons. So that the valency of nitrogen is 3 (trivalent).

Note: Basically, the valency of nitrogen is 5 but it does not have d subshell so that the valency reduces to 3 from 5. For example, phosphorous pentachloride (PCl5) can exist as phosphorus has d-orbitals but nitrogen pentachloride (NCl5) cannot exist. Although nitrogen has 5 valence electrons only a maximum of three can take parts in bond formation [example: NCl3, NH3].

In another sense, a nitrogen atom can form a maximum of three covalent bonds in chemical bonding (For example: NH3, NCl3, etc.), and that what valency is, the maximum ability to form bonds with atoms at the time of chemical reactions.

We can also find the valency of nitrogen with the help of the periodic table. As nitrogen belongs to group 15 (5A or VA) along with nonmetal phosphorus (P), the metalloids arsenic (As) and antimony (Sb), and the metal bismuth (Bi). These group elements are also called pnictogens. All these elements have a valency of 3.

Clarification: Valence electrons and valency are two different aspects. valence electrons mean total electrons present in the outermost shell of the element i.e. in the case of nitrogen , its valence electrons are 5. 

But valency is the combining capacity of an element at the time of chemical bonding. so that valency cannot be negative or positive, it is just a number value between 0 to 7. In the case of nitrogen, valency is 3.