Question

What type of energy sublevel is being filled by the elements in Groups IA/1 and IIA/2?

Short answer

Elements in Groups IA/1 and IIA/2 fill the s sublevel.

Step-by-step solution

Understanding the Periodic Table

The elements in Groups IA/1 and IIA/2 are alkali metals and alkaline earth metals respectively. These groups are located at the far left of the periodic table.

Identifying Energy Sublevels

In the periodic table, the position of an element corresponds to its electron configuration, which is distributed among various energy sublevels labeled as s, p, d, and f.

Determining the Sublevel for Groups IA/1 and IIA/2

For elements in Groups IA/1 and IIA/2, the electrons fill the s sublevel. Specifically, the group IA/1 elements have their outermost electron in the s^1 configuration, and group IIA/2 in s^2 configuration.

Key concepts

Periodic Table

The periodic table is an organized chart of chemical elements, ordered by increasing atomic number which corresponds with the number of protons in an atom. This arrangement not only displays the elements in increasing order but also organizes them into rows called periods and columns known as groups or families.
The elements in each group display similar chemical and physical properties because they have the same number of electrons in their outermost energy levels. Specifically, elements are categorized further into metals, non-metals, and metalloids based on their characteristics. This structure is instrumental in predicting the behaviors and relationships of the elements like whether they gain, lose, or share electrons during chemical reactions.

Energy Sublevels

Electron configuration of atoms involves electrons filling different energy sublevels in a specific order. The sublevels are designated by the letters s, p, d, and f. These sublevels accommodate a certain number of electrons:

• s sublevel can hold up to 2 electrons.
• p sublevel can accommodate 6 electrons.
• d sublevel is capable of holding 10 electrons.
• f sublevel can contain up to 14 electrons.

Electrons fill the lowest energy sublevels first—a rule known as the Aufbau principle. This principle, along with the periodic table, helps chemists determine the electron configuration of an element, which is crucial in understanding its chemical properties and reactivity.

Alkali Metals

Alkali metals are located in Group IA/1 of the periodic table and include elements such as Lithium, Sodium, and Potassium. These elements are characterized by having one electron in their outermost s sublevel, specifically an s^1 configuration. Thus, they are incredibly reactive, especially with water, as they are eager to lose this single outer electron to achieve a stable configuration.
Alkali metals are soft and can be cut with a knife; they have a shiny appearance inside that tarnishes quickly when exposed to air due to oxidation. Their high reactivity demands that they are stored under oil to prevent contact with moisture. These metals play vital roles in various applications, such as in batteries (e.g., Lithium) and sodium-vapor lamps.

Alkaline Earth Metals

Alkaline earth metals are positioned in Group IIA/2 of the periodic table, including elements like Beryllium, Magnesium, and Calcium. These metals have two electrons in their outermost s sublevel, with an s^2 electron configuration. As a result, they are less reactive than alkali metals because they need to lose two electrons to achieve a stable electron arrangement.
These metals have essential roles in our daily lives: Magnesium, for example, is lightweight and used structurally, while Calcium is vital for biological functions and found in bones and teeth. Although less reactive, alkaline earth metals do interact with water and other substances, forming stable compounds, such as Calcium carbonate (limestone), widely used in construction and industrial products.