Quantum Mechanical Model of An Atom, Heisenberg’s Uncertainty Principle
Shrivastav 30 May, 2024
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Quantum Mechanical Model of An Atom : Welcome, fellow explorers of science! Have you ever wondered what lies at the heart of the tiny atoms that make up everything around us? Well, buckle up as we embark on an exhilarating journey into the quantum realm to unravel the mysteries of atomic structure. In this article, we'll delve into the fascinating concept of Heisenberg’s Uncertainty Principle and its role in shaping our understanding of the quantum mechanical model of an atom. So, let's dive in and discover the hidden wonders of the atomic world.
Understanding the Quantum Mechanical Model of an Atom
Before we delve into Heisenberg’s Uncertainty Principle, let's first understand the quantum mechanical model of an atom. Imagine the atom as a miniature solar system, with a nucleus at the centre composed of protons and neutrons, and electrons orbiting around it in specific energy levels or "shells." This model, developed through the contributions of scientists like Niels Bohr and Louis de Broglie, revolutionized our understanding of atomic structure..
Unlike the classical model of the atom, which depicts electrons moving in well-defined orbits, the quantum mechanical model describes electrons as existing in regions of space called orbitals. These orbitals represent the probability distribution of finding an electron at a given location around the nucleus. This wave-like behaviour of electrons is a fundamental principle of quantum mechanics.
Heisenberg’s Uncertainty Principle
Now, let's turn our attention to Heisenberg’s Uncertainty Principle, proposed by the renowned physicist Werner Heisenberg in 1927. This principle is a cornerstone of quantum mechanics and has profound implications for our understanding of the behaviour of particles on the atomic and subatomic scales.
Heisenberg’s Uncertainty Principle states that it is impossible to simultaneously measure certain pairs of physical properties of a particle, such as its position and momentum, with arbitrary precision. In other words, the more precisely we know the position of a particle, the less precisely we can know its momentum, and vice versa.
The uncertainty in measurement of position,
Where h is Planck’s constant.
(i)
When
(ii)
When
Explanation Of Heisenberg’s Uncertainty Principle
Suppose we attempt to measure both the position and momentum of an electron. To pin point the position of the electron we have to use light so that the photon of light strikes the electron and the reflected photon is seen in the microscope. As a result of the hitting, the position as well as the velocity of the electron are disturbed.
Significance of Uncertainty Principle
It rules out the existence of definite paths or trajectories of electrons as stated in Bohr’s Model.
Important Note : The effect of the Heisenberg Uncertainty Principle is significant only for the motion of microscopic objects and is negligible for that of macroscopic objects.
Significance of Uncertainty Principle Solved Example
1. Calculate the uncertainty in the position of a particle when the uncertainty in momentum is
(a) 1 × 10 –3 g cm s –1 (b) zero
Sol.:
(a)
Given
According to Heisenberg’s uncertainty principle
(b)
When the value of
2. The uncertainty in position and velocity of a particle are 10 –10 m and 5.27 × 10 –24 ms –1 respectively.
Calculate the mass of the particle (h = 6.625 × 10 –34 joule second)
Sol.: According to Heisenberg’s uncertainty principle,
3. Calculate the uncertainty in velocity of a cricket ball of mass 150 g if the uncertainty in its position is of the order of 1Å (h = 6.6 × 10 –34 kg m 2 s –1 ).
Sol.:
Quantum Mechanical Model of An Atom FAQs
Q.1 : What is Heisenberg’s Uncertainty Principle?
Q.2 : Why is it called the "Uncertainty Principle"?
Q.3 : What does the Uncertainty Principle imply about the behaviour of particles?
Q.4 : How does the Uncertainty Principle challenge classical physics?
Q.5 : What are some examples of pairs of properties affected by the Uncertainty Principle?
Q.6 : How does the Uncertainty Principle impact experimental measurements?
Q.7 : Can the Uncertainty Principle be overcome with more advanced measurement techniques?
Q.8 : What are the real-life examples illustrating the Uncertainty Principle?
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