Question

Under ordinary conditions of temperature and pressure, nitrogen gas exists as diatomic molecules \(\left(\mathrm{N}_{2}\right) .\) As a result of its electronic configuration, \(\mathrm{N}_{2}\) is very inert and requires extreme conditions before it will react with any other species. What is the electronic ground state configuration of a nitrogen atom (atomic number \(=7) ?\)

Short answer

The electronic ground state configuration of a nitrogen atom (atomic number 7) is \(1s^2 2s^2 2p^3\).

Step-by-step solution

Identify the order of the atomic orbitals

We will use the following order for filling atomic orbitals: 1s, 2s, 2p, 3s, 3p, 4s, and so on. Electrons fill the lowest energy orbitals first, following the Aufbau principle.

Find the electron configuration

Nitrogen has an atomic number of 7, which means it has 7 electrons in its ground state. We distribute these electrons across the orbitals identified in Step 1, as follows: - 1s: Fill with 2 electrons - 2s: Fill with 2 electrons - 2p: Fill with 3 electrons (remaining electrons)

Write the electron configuration notation

Using the information from Step 2, the electron configuration for nitrogen is: \[1s^2 2s^2 2p^3\] This represents the ground state electron configuration of a nitrogen atom.

Key concepts

Diatomic Nitrogen

Nitrogen naturally exists in the atmosphere as diatomic molecules, represented chemically as \(\mathrm{N}_2\). This means each molecule consists of two nitrogen atoms bonded together. Due to its electron configuration, \(\mathrm{N}_2\) becomes highly stable and chemically inert. The triple bond between the two nitrogen atoms requires a significant amount of energy to break, making it less reactive under normal conditions. Nitrogen's stability is crucial for its role in the atmosphere, where it acts as an inert background gas.

Atomic Orbitals

In an atom, electrons are arranged in regions called atomic orbitals. These orbitals can be thought of as "maps" where there is a high probability of finding an electron. Each orbital can hold a specific number of electrons. These orbitals are grouped by energy levels (or shells), which increase as the distance from the nucleus grows. The first shell contains the \(1s\) orbital, followed by subsequent shells containing \(2s\), \(2p\), and so forth. Understanding atomic orbitals is crucial for determining how electrons are distributed across an element, influencing the chemical behavior of elements like nitrogen.

Ground State Configuration

The ground state configuration of an atom is its electron arrangement with the lowest possible energy. For nitrogen, with an atomic number of 7, the ground state electron configuration is \([1s^2 2s^2 2p^3]\). This arrangement indicates how electrons fill the atomic orbitals in nitrogen's most stable form. Each electron attracts to the nucleus and tends to occupy the lowest energy available.

• The \(1s\) orbital is filled first with 2 electrons.
• The \(2s\) orbital follows with another 2 electrons.
• The remaining 3 electrons fill the \(2p\) orbitals.

This specific configuration marks nitrogen's chemical identity and its capacity to form bonds.

Aufbau Principle

The Aufbau Principle is a fundamental concept in chemistry that dictates the order in which electrons fill atomic orbitals. According to this principle, electrons occupy orbitals of lowest energy first before filling higher energy orbitals. For nitrogen, this principle guides the process from \(1s\) to \(2s\) to \(2p\) as electrons are placed in the orbitals. This principle helps explain the sequence of the electron configuration. It answers why different elements form the unique configurations that govern their chemical properties. By following this, scientists can predict and rationalize the behavior of elements under various conditions.