Problem 39 - A Complete Resource Book in Chemistry for JEE Main

Question

The electronic configuration of the most electronegative element is (a) \(1 \mathrm{~s}^{2}, 2 \mathrm{~s}^{2}, 2 \mathrm{p}^{5}\) (b) \(\mathrm{Is}^{2}, 2 \mathrm{~s}^{2}, 2 \mathrm{p}^{4}, 3 \mathrm{~s}^{1}\) (c) \(1 \mathrm{~s}^{2}, 2 \mathrm{~s}^{2}, 2 \mathrm{p}^{6}, 3 \mathrm{~s}^{1}, 3 \mathrm{p}^{5}\) (d) \(1 \mathrm{~s}^{2}, 2 \mathrm{~s}^{2}, 2 \mathrm{p}^{6}, 3 \mathrm{~s}^{2}, 3 \mathrm{p}^{5}\)

Step-by-Step Solution

Answer

Option (a) is the correct electronic configuration of the most electronegative element, fluorine.

Step 1: Identify the Most Electronegative Element

The most electronegative element on the periodic table is fluorine. Knowing this helps us understand its electronic configuration.

Step 2: Recall the Electronic Configuration for Fluorine

The electronic configuration of fluorine is derived from its atomic number which is 9. Thus, the configuration will be: \[ 1 ext{s}^2, 2 ext{s}^2, 2 ext{p}^5 \] This indicates that the 1s and 2s orbitals are fully filled, and the 2p orbital has 5 electrons.

Step 3: Compare Electronic Configurations

Match the given options with the electronic configuration of fluorine. The correct configuration for fluorine is: \[ 1 ext{s}^2, 2 ext{s}^2, 2 ext{p}^5 \] which is given in option (a).

Step 4: Determine the Correct Option

After confirming that option (a) matches the electronic configuration for fluorine, we conclude that (a) is the correct choice as it represents the most electronegative element.

Key Concepts

Electronegativity

Electronegativity is an important concept in chemistry that refers to the ability of an atom to attract electrons towards itself when forming a chemical bond.
It is a measure of how strongly an atom can pull electrons away from another atom it is bonded with.

• Higher electronegativity means stronger attraction for electrons.
• It varies across the periodic table: it increases from left to right across a period and decreases going down a group.
• The most electronegative element is fluorine.

Understanding electronegativity is crucial for predicting bond types and molecular shapes.

Fluorine

Fluorine is the chemical element that is the most electronegative and is represented by the symbol 'F'.
It is at the top right corner of the periodic table in Group 17, also known as the halogens.

• Fluorine is highly reactive due to its high electronegativity and can form bonds with almost all elements.
• Its high reactivity makes it potentially dangerous in its elemental form.
• In nature, fluorine exists mostly in compounds, like in fluorides.

It plays crucial roles in various applications, including toothpaste, where fluoride helps in the prevention of tooth decay.

Atomic Structure

Atomic structure is the composition of an atom, which consists of subatomic particles: protons, neutrons, and electrons.
Understanding these components is key to grasping how electrons are distributed around an atom.

• Protons and neutrons form the nucleus at the center of the atom.
• Electrons orbit the nucleus in energy levels composed of orbitals (s, p, d, f).
• The electronic configuration of an atom like fluorine is dictated by its atomic number, which is 9.

This pattern determines the chemical behavior and reactivity of the atom.

Periodic Table

The periodic table is a systematic arrangement of the chemical elements based on their atomic number, electron configurations, and recurring chemical properties.
It helps chemists understand elements' properties and predict the behavior of chemically similar elements.

• Elements are organized in rows (periods) and columns (groups).
• Fluorine is located in Period 2 and Group 17.
• Across a period, electronegativity increases, helping to identify elements like fluorine as extremely electronegative.

The layout of the periodic table reflects the periodic law, where elements show periodic recurrence of properties, assisting in the prediction and identification of elements' behaviors.