Question

Arrange these elements in order of increasing metallic character: Fr, Sb, In, S, Ba, Se.

Short answer

S (Sulfur) < Se (Selenium) < Sb (Antimony) < In (Indium) < Ba (Barium) < Fr (Francium)

Step-by-step solution

Understanding Metallic Character

Metallic character refers to the level of reactivity typical of metals. It increases as we move left across a period and down a group in the periodic table. This means that the elements farther to the left and lower in the periodic table will have greater metallic character.

Locate the Elements in the Periodic Table

Find the position of each given element (Fr, Sb, In, S, Ba, Se) on the periodic table. This will help determine their relative positions in terms of periods (rows) and groups (columns), which is essential for comparing their metallic characters.

Compare Metallic Character Horizontally Across Periods

For elements within the same period, the further left an element is located, the higher its metallic character. Therefore, compare elements horizontally first to see who is more left.

Compare Metallic Character Vertically Down Groups

For elements within the same group, the further down an element is located, the higher its metallic character. After comparing horizontally, compare elements vertically.

Arrange Elements According to the Trends

Starting with the non-metals, arrange the elements in increasing order of metallic character. Sulfur (S) and Selenium (Se) being non-metals and in the same group as the metalloids and metals given, fall on the extreme non-metallic end. Antimony (Sb) as a metalloid is next, followed by Indium (In), which is a poor metal. Barium (Ba) is a more reactive metal as it’s lower down the same group as selenium and sulfur, hence, it has a greater metallic character than Indium. Francium (Fr) being at the bottom of the alkali metals, is the most metallic of the given elements.

Key concepts

Periodic Table Trends

The periodic table is a roadmap that helps us navigate the vast array of chemical elements. One of the table's primary features is its ability to display trends in the properties of elements, which can be predicted based upon their placement. For example, as we move across a period (from left to right), we generally see a decrease in metallic character. Conversely, as we travel down a group (from top to bottom), metallic character tends to increase.

This pattern is due to the atomic structure of the elements. As atomic number increases across a period, electrons are added to the same energy level but the nucleus gains more protons, creating a greater pull on the electrons. This increased pull makes the atoms less willing to give up electrons—a characteristic trait of metals. Down a group, additional energy levels are added, which shields the outer electrons from the pull of the nucleus, making it easier for these atoms to lose electrons and thus, exhibit increased metallic character.

Reactivity of Metals

The reactivity of metals is an important chemical property, often influencing how an element will behave in a reaction. Metal reactivity increases with greater metallic character, which means the most reactive metals are found on the left side and bottom of the periodic table. Alkali metals, like Lithium (Li) and Francium (Fr), are profoundly reactive, as they have a single electron in their outermost orbit that they can easily lose to form positive ions.

Factors influencing reactivity

Several factors affect metal reactivity. Atomic size, ionization energy, and the shielding effect play crucial roles. Larger atoms with lower ionization energies and greater shielding effects tend to be more reactive. For instance, Francium (Fr), being at the bottom of the alkali metals, has a large atomic radius with a low ionization energy, making it extremely reactive.

Comparing Elements by Properties

To compare elements effectively, scientists look at various properties including metallic character, ionization energy, electronegativity, and atomic size. Metallic character is one such property that varies across the periodic table and influences how an element will interact with others. For instance, metals tend to be good conductors of electricity and heat, are malleable and ductile, and can lose electrons easily to form positive ions. Nonmetals, however, often gain electrons in reactions and form negative ions or covalent bonds.

When sorting elements by their metallic character, such as in the exercise, understanding these underlying properties helps predict and explain the behaviors of elements in chemical reactions and their general uses in chemistry and materials science. It illustrates why, for example, Sulfur (S) and Selenium (Se) are non-conductive and why Francium (Fr) would have a greater tendency to form cations.

Periodic Table Groups and Periods

The periodic table's layout consists of rows called periods and columns known as groups or families. Elements in the same period have the same number of electron shells, while elements in the same group share similar chemical properties and have the same number of electrons in their outermost shell.

Understanding groups and periods

Recognizing the significance of groups and periods aids in predicting how elements will behave. Group 1 contains the alkali metals, which are highly reactive, and as we move to Group 18, we find the noble gases, which are very unreactive. Periodic trends, such as the increase in metallic character down a group, provide a foundational understanding of why certain elements are metals, nonmetals, or metalloids. This systematic organization allows scientists, educators, and students alike to quickly assess the properties of an element based on its position on the table.