Question

Total number of lone pair of electrons in \(\mathrm{XeOF}_{4}\) is: (a) 0 (b) 1 (c) 2 (d) 3

Short answer

The total number of lone pair of electrons in \(\mathrm{XeOF}_4\) is 1 (Option b).

Step-by-step solution

Determine Valence Electrons for Xe

Xenon (Xe) is a noble gas located in group 18 of the periodic table. It has 8 valence electrons. We will start by considering these valence electrons in our calculations.

Determine Electrons Used in Bonding

In the molecule \(\mathrm{XeOF}_{4}\), Xenon forms bonds with one Oxygen atom and four Fluorine atoms. Since each bond involves two electrons, we calculate that \(1 (\text{Oxygen}) + 4 (\text{Fluorine}) = 5 \) bonds. Therefore, \(5 \times 2 = 10\) electrons are used in bonding.

Calculate Lone Pair Electrons

Xenon has 8 valence electrons, and \(10\) electrons are used in bonding, which appears to be more than it initially has. But since xenon can have expanded octets, it uses one lone pair of electrons (2 electrons not involved in bonding) to adjust for the additional electrons used.

Validate with Molecular Structure

The molecular geometry for \(\mathrm{XeOF}_4\) is square pyramidal, which results from the \(\text{AB}_4\text{E}\) formula, where \( \text{E} \) stands for a lone pair. Usually, this configuration means the central atom exerts one lone pair that doesn't participate in any bonds but influences the geometry.

Key concepts

Valence Electrons

Valence electrons are the electrons found in the outermost shell of an atom. These electrons play a critical role in determining how the atom interacts with other atoms. They are responsible for forming chemical bonds, either by sharing or transferring electrons with neighboring atoms. For example, in the noble gas xenon (Xe), which is used in the molecule \(\mathrm{XeOF}_4\), there are 8 valence electrons. Since xenon is in group 18 of the periodic table, it has a full complement of electrons in its outer shell.
Valence electrons dictate many properties of elements, such as reactivity and the types of bonds they can form. When studying molecules like \(\mathrm{XeOF}_4\), counting the valence electrons is a crucial first step. This step allows us to predict how these electrons will be utilized in bonding or remain as lone pairs, influencing molecular structure.

Bonding Electrons

Bonding electrons are those involved in chemical bonds between atoms. In a molecular structure, these electrons are shared or transferred to form stable interactions, reducing the overall energy of the system. A bond forms when two valence electrons from different atoms pair up.
In the molecule \(\mathrm{XeOF}_4\), xenon forms bonds with one oxygen atom and four fluorine atoms. Each bond requires two electrons, resulting in a total of 10 electrons shared through bonds. These electrons are essential for holding the structure of the molecule together, and their distribution affects molecular properties.
Understanding bonding electrons is key to grasping how compounds achieve stability. They play a fundamental role not only in maintaining the integrity of the molecule but also in defining its reaction potential with other substances.

Molecular Geometry

Molecular geometry describes the three-dimensional arrangement of atoms within a molecule. This aspect of molecular science helps us predict the shape and angles between bonds, which determine the physical and chemical properties of the molecule.
The geometry of \(\mathrm{XeOF}_4\) is square pyramidal, identified by the presence of four bonds and one lone pair around the xenon atom, denoted as \(\text{AB}_4\text{E}\). The lone pair, denoted by \(\text{E}\), does not engage in bonding but influences the structure by occupying space and causing repulsions that affect bond angles.
Understanding molecular geometry is crucial for predicting behavior in chemical reactions and interactions. It helps to explain why some molecules are polar, how they align in solid materials, and even why certain chemical reactions occur at specific sites on the molecule.