Question

Arrange the following atoms in order of decreasing electronegativity: \(\mathrm{Br}, \mathrm{Cl}, \mathrm{F}, \mathrm{I}\).

Short answer

The atoms in decreasing electronegativity order are: \( \mathrm{F}, \mathrm{Cl}, \mathrm{Br}, \mathrm{I} \).

Step-by-step solution

Identify Positions on the Periodic Table

Firstly, identify the positions of the given elements \( \mathrm{Br}, \mathrm{Cl}, \mathrm{F}, \mathrm{I} \) on the periodic table. They all belong to group 17 (the halogens). Fluorine (F) is at the top of the group, followed by Chlorine (Cl), Bromine (Br) and then Iodine (I).

Apply Electronegativity Trends

As already described, electronegativity decreases down a group. Hence, for group 17, the electronegativity decreases from F to Cl to Br to I.

Arrange in Decreasing Order

Arranging the given atoms in order of decreasing electronegativity based on their positions in their group, we get: \( \mathrm{F} > \mathrm{Cl} > \mathrm{Br} > \mathrm{I} \).

Key concepts

Periodic Table

The periodic table is a tabular arrangement of chemical elements in order of their atomic numbers. This arrangement reveals recurring chemical properties. The table is divided into rows called periods and columns known as groups. Elements in the same group exhibit similar chemical behavior. This is due to their having the same number of electrons in their outer shell.

Understanding the periodic table helps predict the properties and behaviors of elements. For instance, electronegativity can often be predicted based on an element's position in the table. Electronegativity generally increases across a period from left to right and decreases down a group. This trend explains why elements like fluorine have higher electronegativity than iodine, as explained further in the concept of group 17 and halogens.

Group 17

Group 17 of the periodic table is known as the halogens group. This group includes the elements fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Halogens are highly reactive nonmetals and can often be found in nature as salts when combined with metals.

An important property of halogens is their high electronegativity. They possess strong tendencies to attract electrons from other atoms due to their need to fill their outer electron shell. In Group 17, electronegativity decreases as you move down the column. This means fluorine is the most electronegative, while iodine holds the lowest electronegativity among the halogens listed here. The trend is due to increasing atomic size and increased distance of valence electrons from the nucleus as you move down the group.

Halogens

Halogens are a diverse group of elements located in Group 17 of the periodic table. They include fluorine, chlorine, bromine, iodine, and astatine. The term "halogen" comes from Greek, meaning "salt-former." These elements are called salt-formers because they readily react with metals to form salts.

Halogens have several distinctive properties:

• They exist in various physical states at room temperature (e.g., F and Cl are gases, Br is a liquid, I and At are solids).
• They have high electronegativities, with fluorine having the highest of all elements.
• Their reactivity decreases down the group.

These properties make halogens valuable in many industrial applications such as disinfection, water treatment, and the synthesis of pharmaceuticals. Understanding these properties helps in predicting and explaining their behavior in chemical reactions.