Question

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

Short answer

The elements in order of increasing metallic character: S < Se < Sb < In < Ba < Fr.

Step-by-step solution

- Understand Metallic Character

Metallic character refers to the level of reactivity of a metal. In the periodic table, metallic character increases as you move from right to left across a period and from top to bottom down a group. Understanding this trend is key to arranging elements in order of increasing metallic character.

- Identify Periodic Table Locations

Locate each of the elements on the periodic table. Francium (Fr) is in the alkali metal group and is at the bottom of the group. Antimony (Sb) is a metalloid in group 15. Indium (In) is a post-transition metal in group 13. Sulfur (S) and Selenium (Se) are nonmetals in groups 16. Barium (Ba) is an alkaline earth metal in group 2.

- Arrange Elements Within Their Groups

Within groups, arrange the elements by increasing metallic character from top to bottom. We have S and Se in group 16 with S above Se, so S < Se in metallic character. Similarly, Ba is more metallic than Sb since Ba is in group 2 and Sb in group 15.

- Compare Between Different Groups

Now, compare elements from different groups by their position in periods. Since elements from the left are more metallic than those on the right within the same period, we can deduce that In is more metallic than Sb, and Fr is more metallic than Ba.

- Combine Information to Arrange Elements

Combine the information from the above steps. Since Fr is at the bottom of the alkali metals, it is the most metallic. Ba comes next as an alkaline earth metal. In is a post-transition metal, so it is less metallic than Ba. Sb is a metalloid, making it more metallic than the nonmetals S and Se. From these comparisons, we find the order of increasing metallic character to be S < Se < Sb < In < Ba < Fr.

Key concepts

Periodic Table

The periodic table is a comprehensive chart that organizes chemical elements according to their atomic number, electron configurations, and recurring chemical properties. Elements are arranged in rows called periods and columns known as groups. A key feature of the periodic table is its ability to demonstrate trends, such as the increase or decrease in metallic character.

Elements on the left side are typically metals and are characterized by their shiny appearance, high density, and good electrical conductivity. To the right, you find nonmetals, which are generally poor conductors and lack the luster of metals. Furthermore, the periodic table separates elements into blocks that represent the outer electron configurations, influencing their reactivity and chemical behavior.

Chemical Elements

Chemical elements are the building blocks of matter and consist of atoms with the same number of protons in their nuclei. Currently, there are 118 recognized elements, each with unique properties that classify them as metals, metalloids, or nonmetals.

The diversity in chemical elements arises from variations in the atomic structure, particularly the number of electrons in the outer energy level, or valence shell. Metals tend to lose electrons to form cations, while nonmetals typically gain electrons to form anions. This ability to lose or gain electrons relates directly to an element's metallic character.

Metal Reactivity

Metal reactivity refers to the tendency of a metal to undergo chemical reactions. This reactivity is largely dependent on how easily an atom can lose its outermost electrons to form positive ions (cations). Metals that lose electrons more readily are considered more reactive. This trait is prominent among alkali metals located in group 1 of the periodic table.

For example, francium (Fr) is highly reactive due to its single, loosely held electron in its outer shell, which is eagerly given up in chemical reactions. This characteristic is what defines the metallic character of an element and influences how it is used in various applications.

Group Trends in the Periodic Table

Group trends in the periodic table are patterns in properties that occur for elements within the same column or group. One of the key trends is the change in metallic character, which generally increases as you move down a group. This occurs because atoms grow larger and the outermost electrons are farther from the nucleus, making them easier to remove.

As illustrated by the exercise example, barium (Ba) is more metallic than antimony (Sb) because it is located in group 2, which is collectively more metallic compared to group 15 where Sb is found. Recognizing these trends across the periodic table is essential for understanding the behavior of elements and predicting their reactivity in chemical reactions.