The Effect of Electron Loss on Ion Size

Oct 13, 2025 by leolavanderia.com.br 51 views

Introduction

In the realm of chemistry, atoms are the fundamental building blocks of matter. When an atom gains or loses electrons, it forms ions. Ions are atoms or groups of atoms that have gained or lost electrons, resulting in a net positive or negative charge. In this article, we will delve into the concept of positive ions and explore how they compare in size to their parent atoms.

What are Positive Ions?

Positive ions, also known as cations, are formed when an atom loses one or more electrons. This loss of electrons results in a net positive charge on the ion. The process of forming a positive ion is known as ionization. For example, when a sodium atom (Na) loses an electron, it forms a sodium ion (Na+). The sodium ion has a positive charge due to the loss of an electron.

Why are Positive Ions Smaller than their Parent Atoms?

When an atom loses an electron to form a positive ion, the resulting ion has a smaller size compared to its parent atom. This is because the loss of an electron results in a decrease in the number of electrons surrounding the nucleus. The electrons in an atom occupy specific energy levels or shells, and when an electron is lost, the remaining electrons are drawn closer to the nucleus due to the increased positive charge.

The Effect of Electron Loss on Ion Size

The loss of an electron results in a decrease in the size of the ion due to the following reasons:

Reduced Electron Repulsion: When an electron is lost, the remaining electrons are no longer repelled by the lost electron. This reduction in electron repulsion results in a decrease in the size of the ion.
Increased Nuclear Charge: The loss of an electron results in an increase in the nuclear charge, which attracts the remaining electrons closer to the nucleus. This increased attraction results in a decrease in the size of the ion.
Decreased Electron Shielding: The loss of an electron results in a decrease in electron shielding, which is the ability of inner electrons to shield the outer electrons from the nuclear charge. With reduced electron shielding, the outer electrons are more strongly attracted to the nucleus, resulting in a decrease in the size of the ion.

Examples of Positive Ions and their Parent Atoms

Here are some examples of positive ions and their parent atoms:

Sodium Ion (Na+): The sodium ion is formed when a sodium atom loses an electron. The sodium ion has a smaller size compared to the sodium atom due to the loss of an electron.
Potassium Ion (K+): The potassium ion is formed when a potassium atom loses an electron. The potassium ion has a smaller size compared to the potassium atom due to the loss of an electron.
Calcium Ion (Ca2+): The calcium ion is formed when a calcium atom loses two electrons. The calcium ion has a smaller size compared to the calcium atom due to the loss of two electrons.

Conclusion

In conclusion, a positive ion is smaller than its parent atom due to the loss of an electron. The loss of an electron results in a decrease in the size of the ion due to reduced electron repulsion, increased nuclear charge, and decreased electron shielding. Understanding the concept of positive ions and their size is essential in chemistry, as it helps us understand the behavior of atoms and molecules in various chemical reactions.

References

Chemistry: An Atoms First Approach by Steven S. Zumdahl
General Chemistry: Principles and Modern Applications by Linus Pauling
Chemistry: The Central Science by Theodore L. Brown