Question

Arrange the elements oxygen, sulfur, tellurium, and selenium in order of increasing atomic radii. Is your order an example of a group trend or a period trend?

Short answer

The elements oxygen (O, 48 pm), sulfur (S, 103 pm), selenium (Se, 103 pm), and tellurium (Te, 135 pm) can be arranged in the order of increasing atomic radii as follows: O < S < Se < Te. This order represents a group trend because all elements belong to Group 16 (oxygen family or chalcogens) in different periods of the periodic table. The atomic radii increase as we move down the group.

Step-by-step solution

Find the atomic radii of the elements

To find the atomic radii of the elements, we can refer to the data found in a periodic table or other reference material. The atomic radii are as follows (values in picometers): - Oxygen (O): 48 - Sulfur (S): 103 - Selenium (Se): 103 - Tellurium (Te): 135

Arrange the elements in order of increasing atomic radii

Now that we have the atomic radii, we can arrange the elements in order of increasing atomic radii. This order is: 1. Oxygen (O) - 48 pm 2. Sulfur (S) - 103 pm 3. Selenium (Se) - 103 pm 4. Tellurium (Te) - 135 pm

Determine if it is a group trend or a period trend

A group trend is a pattern that occurs when moving from top to bottom within a group (column) in the periodic table. A period trend is a pattern that occurs when moving from left to right within a period (row) in the periodic table. In this case, all elements belong to Group 16 of the periodic table (oxygen family or chalcogens): - Oxygen (O) - Period 2 - Sulfur (S) - Period 3 - Selenium (Se) - Period 4 - Tellurium (Te) - Period 5 Since the elements belong to the same group but different periods, the trend we observe is a group trend. The atomic radii increase as we move down the group.

Key concepts

Periodic Table

The periodic table is a comprehensive chart that organizes all known elements based on their atomic number, electron configuration, and recurring chemical properties. Each element is positioned in a specific spot that helps predict its characteristics and relationships to other elements.

The periodic table consists of rows called periods and columns known as groups or families. Elements in the same period have a sequence of increasing atomic numbers as you move from left to right. This sequence reflects the increment in proton numbers in their nuclei. Similarly, elements in the same group exhibit similar chemical behaviors and trends due to the comparable configuration of their outermost electrons.

Understanding the layout of the periodic table is crucial for studying chemical properties, including atomic radii trends, which are vital for predicting how elements will interact in chemical reactions.

Group Trend

A group trend refers to the patterns observed as you move down a group (or column) in the periodic table. In terms of atomic structure, as you descend a group, each subsequent element has an additional electron shell compared to the element above it. This results in an increase in atomic size because the outer electrons are further away from the nucleus.

In the case of atomic radii, group trends often show increasing atomic size with each step down the group. This happens because the addition of a new electron shell outweighs the increase in nuclear charge, leading to a less effective attraction between the outer electrons and the nucleus.

• As atomic size increases, elements typically become more metallic.
• This impacts ionization energy and electronegativity, which usually decrease down a group.

Understanding group trends is essential for predicting the behavior of elements within the same group, which in turn can influence their chemical applications and reactivity.

Chalcogens

The chalcogens are the family of elements found in Group 16 of the periodic table. This group includes oxygen, sulfur, selenium, tellurium, and polonium. These elements are commonly referred to as the oxygen family.

Chalcogens are characterized by their ability to form compounds with a wide range of elements, displaying considerable diversity in their chemical behavior. This group's elements can show nonmetallic (oxygen), metalloid (tellurium, polonium), and metallic (selenium) behaviors.

• Oxygen is essential for life and is involved in critical processes like respiration.
• Sulfur is known for its role in biological molecules like amino acids.
• Selenium and tellurium have applications in electronics due to their semiconductor properties.

The diversity of chalcogens arises from their variation across periods in the periodic table, affecting their atomic structure and resulting in group trends such as increasing atomic radii when moving from oxygen to tellurium.

Atomic Structure

Atomic structure refers to the composition and arrangement of an atom's protons, neutrons, and electrons. The nucleus of an atom is composed of positively charged protons and neutrally charged neutrons. Surrounding the nucleus are negatively charged electrons arranged in energy levels or shells.

The number of protons in the nucleus defines the atomic number, which is unique for each element and determines its place on the periodic table. The electrons are organized into shells or orbitals, and their configuration forms the basis for the element's chemical properties and trends such as the size of the atomic radii.

As you descend a group in the periodic table, each element gains an additional electron shell compared to the previous element, which increases the distance between the nucleus and the outermost electrons. Thus, atomic size and radii typically expand due to this effect, leading to group trends in which atomic radii increase down a group, as seen in chalcogens, from oxygen to tellurium.