Question

Arrange the following elements in order of decreasing metallic character: \(\mathrm{Sc}, \mathrm{Fe}, \mathrm{Rb}, \mathrm{Br}, \mathrm{O}, \mathrm{Ca}, \mathrm{F}, \mathrm{Te}.\)

Short answer

The elements arranged in order of decreasing metallic character are: \( \mathrm{Rb}, \mathrm{Ca}, \mathrm{Sc}, \mathrm{Fe}, \mathrm{Te}, \mathrm{Br}, \mathrm{O}, \mathrm{F} \).

Step-by-step solution

Identify the position of each element on the periodic table

First, find each element in the periodic table and assess its position relative to others. Sc (Scandium) belongs to group 3, period 4. Fe (Iron) is in group 8, period 4. Rb (Rubidium) is in group 1, period 5. Br (Bromine) is in group 17, period 4. O (Oxygen) is in group 16, period 2. Ca (Calcium) is in group 2, period 4. F (Fluorine) is in group 17, period 2. Te (Tellurium) is in group 16, period 5.

Apply the rules of periodic trends

We know that the metallic character decreases from left to right across a period and increases from top to bottom in a group. Order them accordingly.

Order the elements

Following these periodic trends, the final arrangement in order of decreasing metallic character is: Rb (Rubidium), Ca (Calcium), Sc (Scandium), Fe (Iron), Te (Tellurium), Br (Bromine), O (Oxygen), F (Fluorine).

Key concepts

Periodic Table

The periodic table is an organized way to display all known chemical elements. It arranges these elements based on increasing atomic number, which is the number of protons found in the nucleus of an atom.
The table is divided into periods (horizontal rows) and groups (vertical columns). Each period indicates elements with the same number of electron shells, while each group contains elements with similar properties.
Elements in the same group often have similar chemical and physical behavior due to having the same number of electrons in their outermost shell. Metals are typically found on the left side and center, nonmetals on the right, and metalloids lie between these two categories. The periodic table is an essential tool for predicting how elements will react chemically.

Periodic Trends

Periodic trends are predictable patterns observed in the periodic table that help us understand how elements behave. Some important periodic trends include atomic size, ionization energy, electronegativity, and metallic character.
Metallic character refers to how easily an element can lose electrons to form positive ions, a common trait of metals. As you move across a period from left to right, metallic character decreases.
This is because atoms tend to gain more electrons and hold onto them more tightly, reducing their tendency to lose electrons. Conversely, as you move down a group, metallic character increases. This is due to the added electron shells, which result in a larger atomic radius, making it easier for the outer electrons to be lost.

• Across a period: Metallic character decreases
• Down a group: Metallic character increases

Element Classification

Elements can be classified into different categories based on their properties, such as metals, nonmetals, and metalloids. Here’s how they differ:
- **Metals**: These are generally solid at room temperature (except for mercury), have a shiny appearance, and are good conductors of heat and electricity. Metals like Sc (Scandium), Fe (Iron), Rb (Rubidium), and Ca (Calcium) are known for their metallic character.
- **Nonmetals**: Found on the upper right side of the periodic table, nonmetals can be gases, liquids, or solids with properties opposite to metals. For example, O (Oxygen) and F (Fluorine) are nonmetals.
- **Metalloids**: These elements have properties of both metals and nonmetals and are found between the two on the periodic table. Te (Tellurium) is an example of a metalloid. Understanding these classifications is crucial as they determine the elements' reactivities and their roles in chemical reactions. Recognizing where an element fits helps predict its behavior when combined with other substances.