KI Molecular Geometry - Science Education and Tutorials

Q: What is the molecular notation for KI molecule?

KI molecular notation is AX1N3.

Potassium iodide(KI) has the composition of one iodine and one potassium atom. What is the molecular geometry of potassium iodide?. Drawing and predicting the KI molecular geometry is very easy by following the given method. Here in this post, we described step by step to construct KI molecular geometry. Iodine and potassium come from the 17th and 1st family groups in the periodic table. Iodine and potassium have seven and one valence electrons respectively.

Table of Contents

Key Points To Consider When drawing The KI Molecular Geometry

A three-step approach for drawing the KI molecular can be used. The first step is to sketch the molecular geometry of the KI molecule, to calculate the lone pairs of the electron in the central iodine atom; the second step is to calculate the KI hybridization, and the third step is to give perfect notation for the KI molecular geometry.

The KI molecular geometry is a diagram that illustrates the number of valence electrons and bond electron pairs in the KI molecule in a specific geometric manner. The geometry of the KI molecule ion can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory) and molecular hybridization theory, which states that molecules will choose the KI geometrical shape in which the electrons have from one another in the specific molecular structure.

Finally, you must add their bond polarities characteristics to compute the strength of the one K-I single bonds (dipole moment properties of the KI molecular geometry). One potassium-iodine single bonds in the potassium iodide(KI), for example, are polarised toward the more electronegative value iodine atom, and because (K-I) single bonds have the same size and polarity, their sum is nonzero due to the KI molecule’s bond dipole moment due to pulling the electron cloud to the two side of linear geometry, and the KI molecule is classified as a polar molecule.

The molecule of potassium iodide(with linear shape KI molecular geometry) is tilted at 180 degrees bond angle of K-I. It has a difference in electronegativity values between iodine and potassium atoms, with iodine’s pull the electron cloud being greater than potassium’s. But bond polarity of K-I is not canceled to each other in the linear geometry. As a result, it has a nonzero permanent dipole moment in its molecular structure. The KI molecule has a nonzero dipole moment due to an unequal charge distribution of negative and positive charges in the linear geometry.

Overview: KI electron and molecular geometry

According to the VSEPR theory, the KI molecule ion possesses linear molecular geometry. Because the center atom, iodine, has one K-I single bond with the one potassium atom surrounding it. The K-I bond angle is 180 degrees in the linear KI molecular geometry. The KI molecule has a linear geometry shape because it contains one potassium atom in the linear and four corners with four lone pairs of electrons.

There is one K-I single bond at the KI molecular geometry. After linking the one potassium atom and four lone pairs of electrons on the iodine atom (as iodide ion) in the linear form, it maintains the linear-shaped structure. In the KI molecular geometry, the K-I single bond has stayed in the one terminal and four lone pairs of electrons on the iodine atom of the linear molecule.

The center iodine atom of KI has four lone pairs of electrons, resulting in linear KI electron geometry. However, the molecular geometry of KI looks linear-shaped and has four lone pairs of electrons on the iodine of the KI geometry. It’s the KI molecule’s slight asymmetrical geometry. As a result, the KI molecule is more polar.

How to find KI hybridization and molecular geometry

Calculating lone pairs of electrons on iodine in the KI geometry:

Determine the number of lone pairs of electrons in the core iodine atom of the Lewis structure. Because the lone pairs of electrons on the iodine atom are mostly responsible for the molecule geometry planar, we need to calculate out how many there are on the central iodine atom of the KI Lewis structure.

Use the formula below to find the lone pair on the iodine atom of the KI molecule.
L.P(I) = V.E(I) – N.A(K-I)

Lone pair on the central iodine atom in KI= L.P(I)
The core central iodine atom’s valence electron in KI= V.E(I)
Number of K-I bond = N.A (K-I)
calculation for iodine atom lone pair in KI molecule.

For instance of KI, the central atom, iodine, has seven electrons in its outermost valence shell, one K-I single bond connection. This gives a total of one connection.

As a result of this, L.P(I) = (8 –0)=8

The lone pair of electrons in the iodine atom of the KI molecule is four.

Calculating lone pair of electrons on potassium in the KI geometry:

Finding lone pair of electrons for the terminal potassium atom is similar to the central iodine atom. We use the following formula as given below

Use the formula below to find the lone pair on the sosium atom of the KI molecule.
L.P(K) = V.E(K) – N.A(K-I)

Lone pair on the terminal potassium atom in KI = L.P(K)
Terminal potassium atom’s valence electron in KI= V.E(K)
Number of K-I bonds = N.A ( K-I)
calculation for potassium atom lone pair in KI molecule.

For instance of KI, their terminal atoms, potassium, have one electron in its outermost valence shell, one K-I single bond connection. This gives a total of one K-I single bond connection. But we are considering only one connection for the calculation.

As a result of this, L.P(K) = (0 –0)=0

The lone pair of electrons in the potassium atom of the KI molecule is zero. One potassium atom is connected with the central iodine atom.

In the KI electron geometry structure, the lone pairs on the central iodine atom are four, lone pairs of electrons in the potassium atom have zero. One potassium atom has no lone pairs of electrons.

It means there are four lone pairs of electrons in the core iodine atom (as iodide ion). Four lone pair of electrons on the central iodine atom is responsible for the linear nature of KI molecular geometry. But in the structure potassium atom is polarised sidewise in their linear geometry.

The four lone pairs of electrons are placed at another side of the KI geometry. Because the potassium atom is a lower electronegative value as compared with other atoms in the KI molecule. One potassium atom is polarized towards the sidewise in the KI structure.

But in reality, the KI has four lone pairs of electrons in its structure. This makes the KI more asymmetrical in the structure of the molecule. Because there is electric repulsion between bond pairs and lone pairs.

But some sort of interaction is there between potassium empty hole and lone pairs of electrons of iodine of another KI molecule. Here, potassium of one molecule acts as an acceptor and iodine of another molecule as a donor. This is called potassium bonding between the two KI molecules. This is one of the main intermolecular forces in KI.

But in the central, iodine atom has four lone pairs of electrons and these lone pair electrons are placed in the four corners of the tetrahedral.

Calculate the number of molecular hybridizations of the KI molecule

What is KI hybridization? This is a very fundamental question in the field of molecular chemistry. All the molecules are made of atoms. In chemistry, atoms are the fundamental particles. There are four different types of orbitals in chemistry. They are named s, p, d, and f orbitals.

The entire periodic table arrangement is based on these orbital theories. Atoms in the periodic table are classified as follows:

s- block elements
p- block elements
d-block elements
f-block elements
Atoms are classified in the periodic table

KI molecule is made of one iodine and a potassium atom. The potassium and iodine atoms have s and p orbitals. But potassium atom has only s orbital in the ground state. Potassium comes as the fourth element in the periodic table. The iodine atom also belongs to the halogen family group. But it falls as the fourth element in the periodic table.

When these atoms combine to form the KI molecule, its atomic orbitals are mixed and form unique molecular orbitals due to hybridization.

How do you find the KI molecule’s hybridization? We must now determine the molecular hybridization number of KI.

The formula of KI molecular hybridization is as follows:
No. Hyb of KI= N.A(K-I bond) + L.P(I)
No. Hy of KI = the number of hybridizations of KI
Number of K-I bonds = N.A (K-I bonds)
Lone pair on the central iodide atom = L.P(I)
Calculation for hybridization number for KI molecule

In the KI molecule, iodine is a core central atom with one potassium atom connected to it. It has four lone pairs of electrons on iodine (as an iodide ion). The number of KI hybridizations (No. Hyb of KI) can then be estimated using the formula below.

No. Hyb of KI= 4+0=4

The KI molecule ion hybridization is four. The iodine and potassium atoms have s and p orbitals. The sp3 hybridization of the KI molecule is formed when one s orbital and three p orbitals join together to form the KI molecular orbital.

Molecular Geometry Notation for KI Molecule :

Determine the form of KI molecular geometry using VSEPR theory. The AXN technique is commonly used when the VSEPR theory is used to calculate the shape of the KI molecule.

The AXN notation of KI molecule is as follows:
The central iodide atom in the K molecule is denoted by the letter A.
The bound pairs (one K-I bonds) of electrons to the core iodide atom are represented by X.
The lone pairs of electrons on the central iodide atom are denoted by the letter N.
Notation for KI molecular geometry

We know that iodide is the core atom, with no electron pair bound (one ionic bond K-I) and four lone pairs of electrons. The general molecular geometry formula for KI is AN4.

According to the VSEPR theory, if the KI molecule ion has an AN4 generic formula, the molecular geometry and electron geometry will both be linear-shaped forms.

Name of Molecule	Potassium iodide
Chemical molecular formula	KI
Molecular geometry of KI	linear
Electron geometry of KI	linear
Hybridization of KI	sp3
Bond angle (K-I)	180º degree
Total Valence electron for KI	8
The formal charge of KI on iodide	0

Summary:

In this post, we discussed the method to construct KI molecular geometry, the method to find the lone pairs of electrons in the central KI atom, KI hybridization, and KI molecular notation. Need to remember that, if you follow the above-said method, you can construct the KI molecular structure very easily.