Physics Revision Notes for Class 12 for Chapter 12 Atoms

The first model of atom proposed by J.J Thomson in 1898, described that the positive charge of the atom is uniformly distributed throughout the atom and the negative electrons are embedded in it like seeds in a watermelon. This model was also known as the plum pudding model of the atom. However, subsequent studies on atoms discussed in this chapter showed that the distribution of protons and electrons in an atom is very different from that proposed in this model. In the early nineteenth century, it was also established each element is associated with a characteristic spectrum of radiation. Since hydrogen is the simplest of elements, we shall consider its spectrum in this chapter. We have provided a concise CBSE class 12 Physics revision for chapter 12 Atoms with important points to remember.

CBSE Notes Class 12 Physics Chapter 12 Atoms

Also Read:

Law of Conservation of Energy Energy Level
Fermi Energy Davisson Gemer Experiment

Frequently asked Questions on CBSE Class 12 Physics Notes Chapter 12: Atoms


What are ‘Alpha’ particles?

Alpha particles are composite particles consisting of two protons and two neutrons tightly bound together.


What does the ‘Balmer series’ refer to?

The Balmer series is the name given to a series of spectral emission lines of the hydrogen atom that result from electron transitions from higher levels down to the energy level with principal quantum number 2.


What is ‘de Broglie hypothesis’?

De Broglie’s hypothesis of matter waves postulates that any particle of matter that has linear momentum is also a wave.


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