Question

Write the electron configuration for \(\mathrm{N}\). Then write the Lewis symbol for \(\mathrm{N}\) and show which electrons from the electron configuration are included in the Lewis symbol.

Short answer

Electron configuration of N: 1s2 2s2 2p3. The Lewis symbol for nitrogen includes these valence electrons as five dots around the symbol 'N': one dot for each of the 2s2 electrons and three separate dots for the 2p3 electrons.

Step-by-step solution

Determine the Atomic Number

Find nitrogen in the periodic table to determine its atomic number, which indicates the number of protons and, in a neutral atom, also the number of electrons. Nitrogen has an atomic number of 7, meaning that a neutral nitrogen atom has 7 electrons.

Write the Electron Configuration

Following the Aufbau principle, fill the electrons into the orbitals in ascending energy order. The first two electrons fill the 1s orbital, the next two fill the 2s orbital, and the remaining three go into the 2p orbitals. This gives us the electron configuration of nitrogen as 1s2 2s2 2p3.

Draw the Lewis Symbol

The Lewis symbol consists of the element's symbol surrounded by dots that represent the valence electrons. For nitrogen, the five valence electrons (2 from 2s and 3 from 2p) are shown as dots around the symbol N. Place one dot on each of the four sides (representing one electron per side) and then pair up as needed to represent the actual electron configuration. Since nitrogen has three unpaired electrons, these are shown as three separate dots.

Identify the Valence Electrons in the Lewis Symbol

The valence electrons are the electrons in the outermost energy level, which are used in the Lewis symbol. In the case of nitrogen, the valence electrons are the 2s2 2p3 electrons. These are the electrons depicted as dots in the Lewis symbol.

Key concepts

Electron Configuration

Understanding the electron configuration of an element, such as nitrogen, is crucial for predicting its chemical behavior. Electron configuration describes the distribution of electrons in the different energy levels and orbitals of an atom. Nitrogen, with an atomic number of 7, has seven electrons.

Following the Aufbau principle, which states that electrons fill orbitals starting from the lowest energy level, nitrogen's electron configuration is written as 1s² 2s² 2p³. Here, the first two electrons occupy the 1s orbital, the next two fill the 2s orbital, and the final three are placed in the 2p orbitals. Understanding this configuration helps us predict the reactivity of nitrogen and form its Lewis symbol accurately.

Valence Electrons

Valence electrons are the electrons in the outermost shell of an atom and are vital in determining how an element will react with others. For nitrogen, these are the electrons in the second energy level, specifically the 2s and 2p orbitals. As calculated in the electron configuration, there are five valence electrons in total: two in the 2s orbital and three in the 2p orbitals.

These valence electrons are represented in nitrogen's Lewis symbol, which depicts the number and arrangement of an atom's valence electrons. Lewis symbols are essential tools for understanding bonding and chemical reactions since they visually illustrate how an atom might form covalent bonds with others.

Aufbau Principle

The Aufbau principle is a fundamental guideline that helps us determine the electron configuration of an atom. According to this principle, electrons are added to an atom's orbitals in order of increasing energy. The lowest energy orbitals are filled first, with one electron entering each orbital before any pairing begins.

The word 'Aufbau' is German for 'building up', which aptly describes how electrons populate atomic orbitals. Considering the Aufbau principle, we can explain why nitrogen's electron configuration starts with filling the 1s orbital, followed by the 2s, and finally spreading out over the 2p orbitals. This principle, combined with Hund's rule and the Pauli exclusion principle, provides a systematic way to write an atom's electron configuration.

Periodic Table

The periodic table is more than just a list of elements; it's a powerful tool that embodies the fundamentals of atomic structure and chemical properties. Each element's placement on the periodic table is indicative of its electronic structure, which is why we can find nitrogen in group 15 and period 2.

These positions confirm nitrogen's electron configuration and valence electrons. The group number for nitrogen indicates it has five valence electrons, aligning with its electron configuration, 1s² 2s² 2p³. The period number implies the highest energy level of the electrons, which for nitrogen is the second level. Understanding the periodic table's arrangement allows for the deduction of these properties and helps students grasp chemical reactivity and trends among various elements.