foreign [Music] various models of the atom have been proposed by eminent scientists over the years these models have increased our understanding of the atomic structure among these models Rutherford suggested that electrons revolve around the nucleus in well-defined orbits but there was a problem with this the motion of electrons in Rutherford's model was unstable because any charged particle moving in a circular path emits electromagnetic radiation thus the electrons would lose energy and fall into the nucleus making the atom highly unstable then which would be a better model of an atom to overcome the objections against Rutherford's model of atom Niels boar in 1913 proposed a new atom model what does this model propose it first proposes that electrons revolve around the nucleus in specific orbits and these orbits are associated with definite energies and are called shells or energy levels these orbits or shells are represented by the letters K L M N the maximum number of electrons that can be accommodated in a particular orbit is 2 N to the power of 2 where n is the number of the orbit thus K shell would have two electrons L shell would have eight electrons M shell would have 18 electrons and N shell would have 32 electrons and so on [Music] that said what does this model next propose itnex proposes that the maximum number of electrons that can be accommodated in the outermost level is eight [Music] and finally it says that the orbit closest to the nucleus has minimum energy and the orbit farthest has a maximum energy well then does an electron radiate energy by itself since electrons move in a particular orbit they do not radiate energy by themselves what happens instead is when an atom absorbs energy the electrons get excited and jump into the next higher energy level the electron can radiate energy and return to its original state or drop down to the next energy level s model works well for simple atoms and is easy to understand it is one among the atomic structure still in use today and the other being the quantum mechanical model things to remember in 1913 a Danish physicist Niels Bohr proposed an atomic model known as Boris atomic model in an atom the electrons revolve around the nucleus indefinite energy levels called orbits or shells the maximum number of electrons that can be accommodated in a particular orbit is to n to the power of 2. the maximum number of electrons that can be accommodated in the outermost shell is eight the orbit closest to the nucleus has minimum energy and the orbit farthest has maximum energy electrons are excited to the higher energy levels by absorbing energy and return to the lower energy levels by radiating energy [Music]