Question

Two \(p\) orbitals from one atom and two \(p\) orbitals from another atom are combined to form molecular orbitals for the joined atoms. How many MOs will result from this combination? Explain.

Short answer

4 molecular orbitals will result from the combination.

Step-by-step solution

Identify the Number of Atomic Orbitals

Each atom is contributing 2 p orbitals to the combination. Therefore, there are a total of 4 atomic orbitals.

Apply the Molecular Orbital Theory

According to molecular orbital theory, when atomic orbitals combine, they form the same number of molecular orbitals. So, if we have 4 atomic orbitals, we will form 4 molecular orbitals.

Summarize the Result

Combining 2 p orbitals from one atom with 2 p orbitals from another atom generates 4 molecular orbitals in total.

Key concepts

p Orbitals

A p orbital is a type of atomic orbital that is shaped like a dumbbell. Each energy level in an atom has three p orbitals, known as the px, py, and pz orbitals. These orbitals are oriented along the x, y, and z axes in three-dimensional space.

Unlike s orbitals, p orbitals have a node at the nucleus where the probability of finding an electron is zero. Electrons in p orbitals have more energy than those in s orbitals of the same energy level.

Understanding the shape and orientation of p orbitals is crucial because when atoms interact to form molecules, these orbitals overlap to form molecular orbitals. The way p orbitals overlap can influence the bonding and properties of the molecule.

Molecular Orbital Theory

Molecular Orbital (MO) Theory is a method for describing the electronic structure of molecules. According to this theory, atomic orbitals from individual atoms combine to form molecular orbitals that spread out over the entire molecule.

These molecular orbitals can either be bonding or antibonding. Bonding orbitals are lower in energy and stabilize the molecule, while antibonding orbitals are higher in energy and can destabilize the molecule if they are occupied by electrons.

The number of molecular orbitals formed is always equal to the number of atomic orbitals combined. For example, if 4 atomic orbitals (2 from each of two atoms) combine, they will form 4 molecular orbitals. This is a key concept in MO theory.

Atomic Orbitals

Atomic orbitals are regions around an atom's nucleus where electrons are most likely to be found. These orbitals come in different shapes and sizes, namely s, p, d, and f orbitals.

The s orbitals are spherical, while p orbitals are dumbbell-shaped. D and f orbitals have even more complex shapes. The number and type of atomic orbitals available for bonding determine how molecules form and their chemical properties.

When these atomic orbitals combine during the formation of a molecule, they create molecular orbitals according to principles described by the molecular orbital theory. The combination of these atomic orbitals dictates the bonding, geometry, and reactivity of the resulting molecule.