Quantum Mechanical Model of Atom

Quantum mechanical model of an atom

An Austrian physicist, Erwin Schrödinger (1887–1961), used the electron’s wave-particle duality to devise and solve a complex mathematical equation that accurately described the behaviour of an electron in a hydrogen atom. The solution to Schrödinger’s equation resulted in the creation of the quantum mechanical model of the atom. To solve the equation, the electron energies must be quantized. Quantization, in contrast to the Bohr model, was simply assumed with no mathematical basis. 

Quantum mechanical model

Quantum mechanics is a fundamental theory of physics that describes natural physical properties at the atomic and subatomic particle scales. It serves as the foundation for all quantum physics, including quantum chemistry, quantum field theory, quantum technology, and quantum information science.

Quantum mechanics differs from classical physics in that energy, momentum, angular momentum, and other quantities of a bound system have discrete values (quantization), objects have both particle and wave properties (wave-particle duality), and there are limits to how accurately a physical quantity’s value can be predicted prior to the measurement given a complete set of initial conditions (the uncertainty principle)

Quantum mechanics enables the calculation of physical system properties and behaviour. It is often used to describe microscopic systems such as molecules, atoms, and subatomic particles. 

Quantum mechanics predictions have been verified experimentally to an extremely high degree of accuracy. A key feature of the theory is that it rarely predicts what will happen with certainty, instead it provides only probabilities. 

By assigning a probability amplitude to each point in space, a wave function can be used to describe a quantum particle, such as an electron. When these amplitudes are subjected to the Born rule, a probability density function for the position of the electron during a measurement experiment is generated.

Quantum Model of an Atom

Scientists discovered early in the 20th century that their current understanding of matter could not explain the behaviour of atoms. To accurately describe how atoms behave, they needed to develop a new view of matter and energy. This is known as quantum theory or quantum mechanical model of an atom. 

According to quantum theory, matter can behave as both a particle and a wave. The wavelike nature of matter is too small to be seen in visible objects encountered in everyday life. 

In contrast, wavelike nature becomes important in microscopic particles such as electrons. As previously stated, electrons in atoms behave like waves. They exist as a fuzzy cloud of negative charge around the nucleus rather than as a single point particle.

To comprehend the quantum model of an atom, we must first grasp some fundamental facts about waves. Waves are regular vibrations that happen on a regular basis. 

Waves are created when one end of a rope is tied to a fixed object and the other end is moved up and down. As a result of this action, waves travel down the rope. 

The highest point reached by the rope is the wave’s crest. The lowest point is referred to as the wave’s trough. Troughs and crests follow each other in a predictable pattern. 

Wavelength is the measure of distance between one trough and the next, or from one crest to the next. The frequency of a wave is defined as the number of wavelengths that pass through a given point in a given amount of time.

Electrons form shells and subshells around the nucleus of an atom. The large numbers (1, 2, 3, 4) in this table represent electron shells (represented as small spheres), the letters (s, p, d) represent subshells within these shells, and the exponents represent the number of electrons present in each subshell. 

Subshells can be subdivided further into orbitals. Each orbital can hold two electrons, and orbitals are represented in the table by horizontal bars that connect pairs of electrons. Each electron’s spin direction is indicated by the small up and down arrows. The spins of electrons in the same orbital are opposite.

Scientists use a set of numbers known as quantum numbers to describe the properties of an electron in an atom. Electrons are a type of particle known as a fermion, and no two fermions can be exactly alike, according to physics. 

As a result, each electron in an atom has unique properties and a unique set of quantum numbers. In an atom, electrons with the same principal quantum number form a shell. 

Two electrons with the same primary quantum number form the first shell. The quantum numbers for one of these electrons are 1, s, 0, 1/2, and the quantum numbers for the other are 1, s, 0, -½.

Conclusion

Over the course of a century, the fundamental ideas of atomic structure evolved from very primitive concepts of how atoms combine to an understanding of atom constituents—a positively charged nucleus surrounded by negatively charged electrons.

Some of Rutherford and Bohr’s ideas are incorporated into the quantum mechanical model of atom structure. The nucleus remains at the heart of the atom, providing the electrical attraction that holds electrons in place. 

Contrary to Bohr’s theory, electrons do not circulate in definite planet-like orbits. The quantum mechanical model of atom recognises electrons’ wavelike nature and offers a framework for viewing electrons as fuzzy clouds of negative charge.