Question

The energy released when an electron is added to the valence shell of a neutral, gaseous, isolated atom is called (a) electronegativity (b) ionization potential (c) electron affinity (d) lattice energy

Short answer

Answer: Electron affinity.

Step-by-step solution

Understanding the Options

First, let us briefly understand each of the provided terms. 1. Electronegativity: It is the ability of an atom in a molecule to attract electrons to itself. 2. Ionization Potential: It is the energy required to remove an electron from a neutral, gaseous, isolated atom. 3. Electron Affinity: It is the energy change when an electron is added to a neutral, gaseous, isolated atom, usually resulting in a negative ion. 4. Lattice Energy: It is the energy released when a crystal lattice is formed from its constituent ions.

Finding the Correct Answer

Now, let's examine which of these options best describes the energy released when an electron is added to the valence shell of a neutral, gaseous, isolated atom. In this process, an electron is being added, indicating that the right term should involve the addition of an electron to an atom. Among the provided options, electron affinity is the only term that refers to the energy change involving the addition of an electron to a neutral atom. So, the correct answer is electron affinity.

Answer

Hence, the correct answer is (c) electron affinity.

Key concepts

Electronegativity

Electronegativity is a fundamental concept in chemistry that describes how strongly an atom attracts electrons when it is bonded to another atom within a molecule. Different atoms have varying abilities to pull electrons towards themselves, which is quantified by electronegativity.
The concept was first introduced by Linus Pauling, and it plays a crucial role in understanding molecular behavior and chemical reactions.

• Elements with high electronegativity, like fluorine, oxygen, and nitrogen, tend to attract electrons more strongly.
• These elements are more likely to form polar bonds, where electrons are more localized towards the more electronegative atom.
• In a periodic table, electronegativity generally increases across a period and decreases down a group.

By understanding electronegativity, chemists can predict the nature of bonds, whether they will be ionic, polar covalent, or non-polar covalent. This concept is key to foreseeing molecular interactions and the solubility of different compounds.

Ionization Potential

The ionization potential, also known as ionization energy, is a term used to describe the amount of energy required to remove an electron from a neutral, gaseous atom. This process results in the formation of a cation or a positively charged ion.
Ionization potential is an important aspect of atomic properties, reflecting an element's reactivity and stability.

• Ionization energy typically increases across a period due to the increasing nuclear charge, which holds the electrons more tightly.
• Conversely, it tends to decrease down a group as electrons are farther from the nucleus and are more easily removed.

Understanding ionization potential helps predict an element's ability to partake in chemical reactions. Elements with low ionization energy, like those in Group 1 of the periodic table, readily lose electrons and form positive ions, making them highly reactive.

Lattice Energy

Lattice energy is a concept referring to the energy released when positive and negative ions come together to form a crystalline solid, typically an ionic compound.
This energy is an indication of the strength of the forces holding the ions together within the lattice structure.

• The greater the lattice energy, the stronger the ionic bond is and the more stable the compound.
• This energy depends significantly on the size and charge of the ions; smaller, highly charged ions result in greater lattice energies.
• Lattice energy affects properties such as melting point, hardness, and solubility of ionic compounds.

Understanding lattice energy is crucial for predicting the physical properties of materials and the stability of ionic compounds in various chemical environments.