Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 5: Problem 19

Locate \(\mathrm{F}\) and \(\mathrm{Cl}\) on the periodic table. a) Describe any relationship between the core charge of these atoms, the number of valence electrons, and their position in the periodic table. b) Describe any relationship between the valence shell of these atoms and their position in the periodic table. c) Within our model and referring to the Coulombic Potential Energy expression, explain why the \(\mathrm{IE}_{1}\) of \(\mathrm{Cl}\) is less than that of \(\mathrm{F}\).

Short Answer

Expert verified
Both elements, Fluorine and Chlorine, belong to Group 17, making them have the same core charge of +7 and 7 valence electrons. However, Fluorine's valence shell is in the 2nd energy level, while Chlorine's is in the 3rd. This positioning in different periods results in Fluorine having a higher ionization energy than Chlorine due to a stronger Coulombic attraction between its nucleus and the valence electron.

Step by step solution

01

Examining Core Charge and Valence electrons

Locate elements F (Fluorine) and Cl (Chlorine) on the Periodic Table. They are found in Group 17 (also known as Halogens). Fluorine is in period 2, and Chlorine is in period 3. The 'Group' number indicates the number of valence electrons, meaning that both Fluorine and Chlorine have 7 valence electrons. The core charge, or effective nuclear charge, refers to the positive charge experienced by an electron from the nucleus. As we move across a period from left to right, the core charge increases due to greater nuclear charge and negligible increase in shielding effect. Both elements have the same core charge of +7.
02

Understanding Valence Shell Relationship

The Valence shell of an atom refers to the outermost shell. The 'Period' in the periodic table corresponds to the principal quantum number (n), which determines the energy level or shell in which electrons reside. Hence, Fluorine has its valence electrons in the 2nd shell, while Chlorine has its valence electrons in the 3rd shell.
03

Comparing Ionization Energy

Ionization energy (IE) is the energy required to remove an electron from a gaseous atom or ion. Fluorine has higher IE than Chlorine because it's smaller (its valence electrons are in 2nd shell) and experiences a greater attraction to the positively charged nucleus, making it difficult to remove an electron. Additionally, due to the higher core charge of Fluorine, the Coulombic attraction between the nucleus and the electron is stronger; thus, more energy (higher IE) is needed to overcome this attraction. Conversely, for Chlorine, since the valence electrons are further from the nucleus (in the 3rd shell), removal requires less energy (lower IE).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Ionization Energy (IE)
Ionization energy (IE) is a crucial concept when examining atomic structure, and it denotes the amount of energy necessary to detach an electron from a neutral atom in its gaseous state.

Think of it as trying to take a book from a stack against a spring that's pressing down on it; the tighter the spring (nucleus), and the higher the book (electron) is in the stack (closer to the nucleus), the more effort (energy) it requires.

This is why atoms like fluorine with electrons closer to the nucleus (second energy level) have higher IE compared to chlorine, where valence electrons are located farther away (third energy level).
Valence Electrons
The outermost electrons of an atom are known as valence electrons, and they play a pivotal role in chemical bonding and properties.

Using a 'family portrait' analogy, valence electrons are like the children standing in the front row; they are the most visible and interactive members of the family (atom).

In the periodic table, group numbers help identify the number of valence electrons; for instance, the halogens group, which includes fluorine and chlorine, always have seven valence electrons, which affects their chemical behavior and reactivity.
Effective Nuclear Charge
The effective nuclear charge is the net positive charge experienced by valence electrons, which is essential for determining an atom's ability to attract and hold onto its own or other atoms' electrons.

Imagine a magnet (nucleus) with several layers of paper (inner electrons) between it and metal filings (valence electrons). The filings only 'feel' part of the magnet's strength because of the paper layers. Similarly, valence electrons feel the nucleus's pull through the shielding effect of inner electron layers.

Within the halogens group, fluorine and chlorine share the same effective nuclear charge, imparting similar chemical characteristics to these elements.
Coulombic Potential Energy
Coulombic potential energy refers to the energy of interaction between charged particles, which is inversely related to the distance separating them.

Think of this like two opposing magnets; the closer they are, the stronger the pull (or potential energy). This concept helps us understand why the ionization energy of chlorine is less than fluorine. Although both have the same effective nuclear charge, the increased distance between the valence electrons and the nucleus in chlorine means a weaker attraction (less potential energy) compared to fluorine, making it easier to remove an electron (lower IE).
Halogens Group
The halogens group is a significant family of elements in the periodic table, recognized for their electronegativity and reactivity, primarily due to their seven valence electrons.

The group showcase a diverse set of physical and chemical properties. For instance, while fluorine is highly reactive and the most electronegative element, iodine shows comparatively lesser reactivity. Halogens often seek to gain one additional electron during chemical reactions to achieve a stable octet configuration, reflecting a common trait in their chemical behavior.
Atomic Structure
Atomic structure refers to the composition and arrangement of electrons, protons, and neutrons within an atom.

It is like the architecture of a building, with a central core (nucleus) made of protons and neutrons, around which electrons orbit in different levels or 'shells'. Understanding atomic structure is vital, as it influences an element's reactivity, its ionization energy, and how it bonds with other atoms. For example, differences in atomic structure between fluorine and chlorine atoms are what make their ionization energies distinct.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

a) Why is the nuclear charge of Be "+4"? b) How many inner-shell electrons does Be have? c) How many valence electrons does Be have? d) Show how the core charge for Be was calculated. e) What is the relationship between the number of valence electrons and the core charge of a neutral atom?

Assuming that the valence shells of \(\mathrm{Li}\) and \(\mathrm{Be}\) are at approximately the same distance from their nuclei, explain how the core charges of \(\mathrm{Li}\) and \(\mathrm{Be}\) are consistent with the \(\mathrm{IE}_{1}\) values for \(\mathrm{Li}(0.52 \mathrm{MJ} / \mathrm{mole})\) and Be \((0.90 \mathrm{MJ} / \mathrm{mole})\).

How many electrons does Na have in shell \(n=1 ? n=2 ? n=3\) ?

How many inner-shell electrons are there in a) H? b) Li? C) He?

Within our model and referring to the Coulombic Potential Energy expression, explain why the IE increases from left to right across a row of the periodic table.
See all solutions

Recommended explanations on Chemistry Textbooks

Inorganic Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Organic Chemistry

Read Explanation

The Earths Atmosphere

Read Explanation

Chemistry Branches

Read Explanation

Making Measurements

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free