A nitrogen atom has three unpaired electrons. This count is determined by analyzing its electron configuration and applying fundamental principles of electron orbital filling.
Understanding Unpaired Electrons
Unpaired electrons are single electrons that occupy an atomic orbital without another electron of opposite spin. The presence and number of unpaired electrons are key factors influencing an atom's magnetic properties and its ability to form chemical bonds.
Determining Unpaired Electrons in Nitrogen
Nitrogen (N) is element number 7 on the periodic table, meaning a neutral nitrogen atom contains 7 electrons. To find the number of unpaired electrons, we must determine how these electrons fill the available atomic orbitals by following these established rules:
- Aufbau Principle: Electrons first occupy the lowest energy orbitals available.
- Pauli Exclusion Principle: Each atomic orbital can hold a maximum of two electrons, and these two electrons must have opposite spins.
- Hund's Rule: For orbitals of the same energy level (degenerate orbitals), electrons will individually occupy each orbital with parallel spins before any pairing occurs within an orbital.
Electron Configuration of Nitrogen
The full electron configuration for a nitrogen atom is 1s² 2s² 2p³. Let's examine each part of this configuration:
- 1s orbital: Contains 2 electrons. Since an s-orbital can hold only two electrons, these two electrons are paired.
- 2s orbital: Also contains 2 electrons. Similar to the 1s orbital, these two electrons are paired.
- 2p subshell: Contains 3 electrons. The 2p subshell is composed of three degenerate orbitals (often designated as 2px, 2py, and 2pz).
Applying Hund's Rule to the 2p Subshell
According to Hund's Rule, the three electrons in the 2p subshell will each occupy one of the three available 2p orbitals individually. Since there are exactly three electrons and three 2p orbitals, each orbital receives one electron. These electrons all have parallel spins, meaning they remain unpaired.
Therefore, the distribution in the 2p subshell is effectively:
- One electron in 2pₓ
- One electron in 2pᵧ
- One electron in 2p₂
All three of these electrons are unpaired.
Summary of Electrons in Nitrogen
The table below summarizes the electron distribution and the number of unpaired electrons within a nitrogen atom:
| Orbital | Number of Electrons | Paired Electrons | Unpaired Electrons |
|---|---|---|---|
| 1s | 2 | 2 | 0 |
| 2s | 2 | 2 | 0 |
| 2p | 3 | 0 | 3 |
| Total | 7 | 4 | 3 |
As illustrated, the three electrons residing in the 2p subshell are the unpaired electrons, which significantly influences nitrogen's bonding characteristics, typically allowing it to form three covalent bonds.
Further Resources:
- Learn more about Electron Configuration
- Understand the principles behind Hund's Rule and the Pauli Exclusion Principle
