Question

Electrons found in the outermost principal energy level of an atom are referred to as ______ electrons.

Short answer

Valence electrons

Step-by-step solution

Identify the electrons in the outermost principal energy level

To solve this exercise, we need to remember that electrons in the outermost shell of an atom play a key role in chemical reactions and bonding. They have a specific name, which characterizes their position and function in the atom.

Recall the term for these electrons

The electrons found in the outermost principal energy level of an atom are referred to as \(\textit{valence electrons}\).

Key concepts

Outermost Principal Energy Level

The outermost principal energy level in an atom is a crucial concept because it determines the atom's ability to interact with other atoms. This energy level is essentially the outermost shell where electrons are present. The electrons in this level experience the least amount of attraction from the nucleus due to being the furthest away.
The outermost principal energy level is important because:

• It affects how atoms share or transfer electrons during chemical reactions.
• Determines the reactivity of an element, as elements with less than a full outer shell tend to be more reactive.
• Helps to predict how an element will form compounds with other elements using those electrons.

Understanding the outermost principal energy level can help in grasping why certain elements behave the way they do during interactions. This knowledge is foundational to exploring deeper chemical concepts like bonding and electron configurations.

Chemical Bonding

Chemical bonding is the process by which atoms interact and combine to form molecules and compounds. It is primarily facilitated by the electrons located in an atom's outermost principal energy level, known as valence electrons.
Chemical bonding can be categorized into different types, such as:

• Ionic Bonding: This occurs when electrons are transferred from one atom to another, resulting in the formation of positive and negative ions. It mostly happens between metals and non-metals.
• Covalent Bonding: Atoms share electrons to achieve full outer shells, usually happening between non-metal atoms. This sharing helps them achieve a more stable electron arrangement.

Bonding is essential because:

• It determines the structure and stability of substances.
• Results in the formation of compounds with unique properties different from their constituting elements.
• Aids in understanding how different substances interact with one another.

The nature of chemical bonds influences the physical properties such as melting and boiling points, solubility, and electrical conductivity.

Electron Configuration

Electron configuration describes the arrangement of electrons in an atom’s orbitals. An atom’s electron configuration is critical in determining its chemical properties and how it bonds with other atoms.
Representation of electron configuration is based on the periodic table structure using energy levels and orbitals.

• Energy Levels: Also referred to as shells, these are the large circles in which electrons orbit around the nucleus, labeled as 1, 2, 3, etc.
• Sublevels: These are sections of energy levels composed of orbitals (s, p, d, f) which further hold the electrons.

When writing electron configurations, it follows the principle of adding electrons to the lowest energy orbitals first — known as the Aufbau principle. Following this helps us understand:

• How elements are grouped in the periodic table.
• The number of valence electrons present, which influences the manner of chemical bonding.
• The reasons behind an atom’s reactivity and stability.

By mastering electron configuration, one can predict the chemical behavior of an element, thereby connecting the microscopic atomic world with macroscopic chemical reactions.