Bohr model of atom

In the Bohr model of atomic structure, electrons are constrained to orbit a nucleus at specific distances, given by the equation... 

The electrons are negatively charged particles. The mass of an electron is about 2000 times smaller than that of an proton or neutron at 0.00055 amu. Electrons circle so fast that it cannot be determined where electrons are at any point in time, rather, we talk about the probability of finding an electron at a point in space relative to a nucleus at any point in time. The image depicts the old Bohr model of the atom, in which the electrons inhabit discrete "orbitals" around the nucleus much like planets orbit the sun. This model is outdated. Current models of the atomic structure hold that electrons occupy fuzzy clouds around the nucleus of specific shapes, some spherical, some dumbbell shaped, some with even more complex shapes. Even though the simpler Bohr model of atomic structure has been superseded, we still refer to these electron clouds as "orbitals". The number of electrons and the nature of the orbitals they occupy basically determines the chemical properties and reactivity of all atoms and molecules. 

According to Pauli s exclusion principle, each electron must be in a unique quantum state. Since electrons can have two spin orientations (ms= + /2 and nis = —V2), only two electrons with opposite spins can have the same velocity v. This case is analogous to the Bohr model of atoms, in which each orbital can be occupied by two electrons at maximum. In solid-state physics, the wavevectork = (4, ky, 4) of a particle is more frequently used instead of its velocity to describe the particle s state. 

Every molecule is made up from the nuclei and electrons of two or more atoms via bonds that result from the overlap of atomic orbitals. Hence, the shapes and properties of atomic orbitals are of paramount importance in dictating the bonding in and properties of molecules. The Bohr model of atoms had electrons moving in specific orbits (hence the term orbitals) around the nucleus. We now view the shapes and properties of atomic orbitals as they are obtained from basic quantum mechanics via solution of the Schrodinger equation. The solutions to the Schrodinger equation are termed wavefunctions, and in their most common implementation these wavefunctions correspond to atomic or molecular orbitals. 

The Bohr model of atomic structure was introduced in Chapter 2. This model has the following... 

Bohr model of atomic structure Atomic number... 

The role of chemistry in Bohr s atomic theory is discussed in Helge Kragh, Niels Bohr and the Quantum Atom The Bohr Model of Atomic Structure 1913-1925 (Oxford Oxford University Press, 2012). 

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