Problem 13 - General Chemistry: Principles and Modern Applications

Question

Which is (a) the smallest atom in group \(13 ;\) (b) the smallest of the following atoms: Te, In, Sr, Po, Sb? Why?

Step-by-Step Solution

Answer

The smallest atom in group \(13\) is Boron (B) and the smallest atom among Te, In, Sr, Po, Sb is Tellurium (Te) due to atomic size trends on the periodic table.

Step 1: Identify Group 13 elements

First, identify all the elements in group 13. Group 13 of the periodic table consists of the elements Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), Thallium (Tl), and element 113 (Ununtrium, Uut).

Step 2: Find the smallest atom in Group 13

According to the atomic size trend, the atomic size increases as you move down a group because each subsequent element has an additional energy level. Therefore, Boron (B), being at the top of Group 13, is the smallest atom in this group.

Step 3: Identify given elements

Identify the provided elements: Tellurium (Te), Indium (In), Strontium (Sr), Polonium (Po), and Antimony (Sb).

Step 4: Compare atomic radii to determine the smallest atom

Using the trend of atomic size, the further to the right and down you go on the periodic table, the larger the atom. In this item selection, Tellurium (Te) is farthest to the right and has the smallest atomic radius.

Step 5: Explain why certain elements have smaller atomic radii

The size of atoms (atomic radii) within a period or row on the periodic table decreases from left to right because of the increasing positive charge of the nucleus, which pulls the electrons closer to the center of the atom, causing the size to decrease.

Key Concepts

Periodic Table Groups

The periodic table is a structured array where elements are sorted by increasing atomic number, forming columns known as groups and rows known as periods. Groups are particularly important as they contain elements with similar chemical properties due to having the same number of valence electrons.

Group 13 of the periodic table comprises six elements: Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), Thallium (Tl), and element 113, known as Nihonium (Nh). As you move down Group 13, elements acquire extra electron shells, which is an important factor influencing atomic size trends.

What's fascinating about these groups is how they help us predict the behavior and characteristics of elements. Elements in Group 13 typically feature three electrons in their outermost shell, which allows them to bond in specific ways, often forming compounds with other nonmetals. Understanding the structure of periodic table groups aids in comprehending atomic size and reactivity of the elements.

Atomic Radii Comparison

Atomic radii refer to the approximate size of an atom, measured from the nucleus to the outermost stable electron orbit. In the periodic table, there are general trends associated with changes in atomic radii both across periods and down groups.

- **Down a Group:** As you move down a group, like Group 13, the atomic radii increase. This is because each subsequent element gains an additional electron shell, meaning the outer electrons are farther from the nucleus. - **Across a Period:** Conversely, as you move from left to right across a period, the atomic radii tend to decrease. This happens because, while electrons are being added to the same electron shell, the increased positive charge of the nucleus pulls the electron cloud closer to itself.

For example, within Group 13, Boron (B) at the top has the smallest atomic radius due to fewer electron shells. Across different periods, Tellurium (Te) may have a smaller radius than elements with fewer protons in the same row due to greater nuclear pull. Recognizing these trends can help you understand why certain elements have smaller or larger sizes compared to their neighbors on the periodic table.

Group 13 Elements

The elements in Group 13 of the periodic table provide an excellent example of how atomic size trends work. Boron (B) is the first element in this group, and it is significantly smaller in size compared to the others like Aluminum (Al), Gallium (Ga), and Indium (In). As mentioned before, the increase in atomic radius when moving down the group is attributed to each element having more electron shells.

Boron is known for its ability to form stable covalent bonds and is mostly used in applications involving glass and borates. Aluminum is widely used in construction and packaging due to its lightweight and corrosion resistance. Gallium and Indium are both useful in electronics and semiconductors, thanks to their ability to form useful alloys.

Understanding the unique qualities of Group 13 elements, not just their sizes, can help in predicting their behavior in various chemical reactions and applications. Each element's size and valence electron configuration play key roles in how they interact with other substances. This understanding enhances our ability to manipulate and utilize these elements in a plethora of fields.