Question

Using periodic trends, arrange the following atoms in order of increasing electronegativity. (a) \(\mathrm{Br}, \mathrm{Cl}, \mathrm{F}, \mathrm{N}, \mathrm{O}\) (b) \(\mathrm{C}, \mathrm{F}, \mathrm{H}, \mathrm{N}, \mathrm{O}\)

Short answer

The atoms arranged in order of increasing electronegativity are as follows: (a) \( \mathrm{Br} < \mathrm{Cl} < \mathrm{F} < \mathrm{O} < \mathrm{N} \) (b) \( \mathrm{H} < \mathrm{C} < \mathrm{N} < \mathrm{O} < \mathrm{F} \)

Step-by-step solution

Understand Periodic Trends

Before beginning to solve, it's vital to understand the periodic trends in electronegativity. Electronegativity generally increases from left to right across periods and decreases down groups on the periodic table.

Arrange Set (a) in Increasing Electronegativity

(a) Br, Cl, F, N, O: Given that electronegativity increases from left to right across periods and decreases down groups, the order of increasing electronegativity would be \(Br < Cl < F < O < N\).

Arrange Set (b) in Increasing Electronegativity

(b) C, F, H, N, O: The order of increasing electronegativity for this set using the same criteria would be \(H < C < N < O < F \).

Key concepts

Periodic Trends

Periodic trends are essential patterns observed across the periodic table that help predict an element's chemical properties. One such trend is electronegativity, which increases as you move from left to right across a period. This is because elements on the right side tend to have more protons and a greater ability to attract electrons.
On the other hand, electronegativity generally decreases as you move down a group. This is due to the increasing distance between the nucleus and the outer electron shell as the number of electron shells increases. This extra distance decreases an atom's ability to attract electrons.
Understanding these periodic trends enables us to predict and compare electronegativities among different elements, as seen in the exercise where we arranged elements in order of increasing electronegativity.

Periodic Table

The periodic table is a systematic arrangement of elements, organized by increasing atomic number. It is divided into periods (horizontal rows) and groups (vertical columns). This ingenious table reveals periodic patterns, helping chemists predict chemical behavior.
• **Periods:** Elements in the same period have the same number of electron shells. Moving from left to right, elements generally become less metallic and more nonmetallic, which relates to the increase in electronegativity.
• **Groups:** Elements in the same group share similar chemical properties because they have the same number of valence electrons. These shared characteristics make it easier to understand how they might interact with other elements. By using the periodic table in the exercise, we effectively utilized the concept that electronegativity rises across a period and drops down a group to arrange elements correctly.

Atoms

Atoms are the fundamental building blocks of matter, consisting of a nucleus surrounded by electrons. Each atom's behavior and properties are determined by its electron configuration, especially the outermost electrons known as valence electrons.
• **Electronegativity:** This concept relates to an atom's ability to attract and hold onto electrons within a molecule. In general, smaller atoms with tightly held valence electrons exhibit higher electronegativity.
• **Nucleus and Electrons:** The nucleus, made up of protons and neutrons, exerts a positive charge. Electrons are negatively charged and orbit the nucleus in various energy levels. The number of protons in the nucleus (atomic number) is crucial as it defines the element and its position in the periodic table.
Mastering the concept of atoms and their components is essential in comprehending periodically varying properties like electronegativity, which was a key part of solving the exercise correctly by understanding which atoms attract electrons more strongly.