Write the postulates of Bohr’s theory of atoms.

Bohr's theory of atoms, also known as the Bohr model or Bohr's atomic model, was proposed by Niels Bohr in 1913. It provided a groundbreaking understanding of the structure of atoms and their behavior. The postulates of Bohr's theory are as follows:

Postulate of Stationary Orbits: Bohr proposed that electrons can only occupy specific, discrete energy levels or orbits around the nucleus. These orbits are often referred to as "stationary orbits" or "energy shells." Each orbit is associated with a specific energy value, and electrons can transition between these orbits by either absorbing or emitting quantized amounts of energy.

Postulate of Quantized Energy: Bohr suggested that electrons in an atom can only have certain quantized energy values corresponding to the allowed energy levels or orbits. When an electron moves from one orbit to another, it either absorbs or emits energy in discrete packets called "quanta."

Postulate of Angular Momentum Quantization: Bohr proposed that the angular momentum of an electron in its allowed orbit is quantized. The angular momentum is given by the product of the electron's mass, its velocity, and the radius of the orbit. This postulate helped explain why only specific orbits were allowed for electrons in an atom.

Postulate of Radiation: According to Bohr's theory, electrons can emit or absorb electromagnetic radiation when they transition between different energy levels. When an electron moves from an outer orbit to an inner orbit, it emits energy in the form of electromagnetic radiation, typically in the visible or ultraviolet range. Conversely, when an electron absorbs energy, it moves to a higher energy level.

Postulate of Stability: Bohr's model emphasized that an electron in an atom is most stable when it occupies the lowest possible energy level, also known as the ground state. This stable configuration corresponds to the electron being in the innermost orbit. If an electron gains excess energy, it can jump to a higher orbit, but it eventually loses energy and returns to a more stable orbit.

These postulates formed the basis of Bohr's model and played a crucial role in the development of quantum mechanics. Although the Bohr model has its limitations and was later replaced by more advanced theories, it was a fundamental step in understanding the behavior of electrons in atoms and laid the groundwork for modern atomic physics.