Question

Look at the periodic table, and then order the following elements according to decreasing electronegativity: \(\mathrm{C}, \mathrm{Ca},\) \(\mathrm{Cs}, \mathrm{Cl}, \mathrm{Cu}\).

Short answer

Order: Cl, C, Cu, Ca, Cs.

Step-by-step solution

Identify the Electronegativity Trend

Electronegativity generally increases across a period (from left to right) and decreases down a group (from top to bottom) on the periodic table.

Locate Elements on the Periodic Table

Find the positions of the given elements on the periodic table. - Carbon (C) is in group 14, period 2. - Calcium (Ca) is in group 2, period 4. - Cesium (Cs) is in group 1, period 6. - Chlorine (Cl) is in group 17, period 3. - Copper (Cu) is in group 11, period 4.

Determine Electronegativity Values

Use the periodic table or a trusted reference to find the electronegativity values for each element: - Carbon (C): 2.55 - Calcium (Ca): 1.00 - Cesium (Cs): 0.79 - Chlorine (Cl): 3.16 - Copper (Cu): 1.90

Order Elements by Decreasing Electronegativity

Arrange the elements from the highest to the lowest electronegativity value. Step down the values: - Chlorine (Cl): 3.16 - Carbon (C): 2.55 - Copper (Cu): 1.90 - Calcium (Ca): 1.00 - Cesium (Cs): 0.79

Key concepts

Periodic Table

The periodic table is an essential tool in chemistry that organizes chemical elements in a structured manner. Arranged by increasing atomic number, which is the number of protons in an atom's nucleus, it helps us understand the properties and behaviors of elements.
The periodic table is structured in rows called periods and columns known as groups. Each period and group share certain characteristics:

• **Periods:** As we move from left to right across a period, elements gain more protons and electrons, making them smaller because the increased positive charge pulls electrons closer to the nucleus.
• **Groups:** Elements in the same group have similar valence electron configurations, which means they usually share similar chemical properties.

Groups are designated from 1 to 18. For example, Group 1 contains alkali metals like cesium, while Group 17 consists of halogens like chlorine.
Understanding the periodic table helps predict how elements interact in chemical reactions based on their positions.

Chemical Elements

Chemical elements are the building blocks of matter. Each element is distinguished by the number of protons in its nucleus, called the atomic number, which gives the element its unique identity.
Each element has distinct characteristics:

• **Atomic Number:** Determines the position of the element on the periodic table. For instance, carbon with atomic number 6 is found in group 14.
• **Chemical Symbol:** A unique one or two-letter abbreviation, like "C" for carbon or "Cl" for chlorine.
• **Electronegativity:** A measure of how strongly an atom attracts bonding electrons. Elements with higher electronegativity, like chlorine, are good at attracting electrons.

When we refer to chemical elements in the periodic table, we focus on their properties like electronegativity, atomic weight, and valence electrons, which influence their reactions and bonding patterns.
Knowing these properties is crucial for predicting how different chemical elements will behave in a reaction.

Electronegativity Trend

Electronegativity is a key concept in understanding chemical bonding. It refers to an element's ability to attract and hold electrons when forming a chemical bond.
The trend of electronegativity on the periodic table helps predict how elements interact:

• **Across a Period:** Electronegativity generally increases as you move from left to right. This is because atoms have more protons in their nucleus while maintaining the same energy level, causing a stronger pull on electrons.
• **Down a Group:** Electronegativity usually decreases as you move down a group. As atoms increase in size, the outer electrons are farther from the nucleus and are less tightly held.

In the context of the given exercise, chlorine, which is towards the upper right of the table, naturally has a higher electronegativity than elements like cesium, found lower down and to the left.
This trend helps in predicting the order of electronegativity for different elements, making it easier to anticipate their roles in chemical reactions.