Lithium atom the deviation from hydrogenic energy levels. Lithium atom A lithium atom is an atom of the chemical element lithium. Lithium is composed of three electrons bound by the electromagnetic force to a nucleus containing three protons along with either three or four neutrons, depending on the isotope, held together by the strong force. Similarly to the case of the helium atom, a closed-form solution to the Schrödinger equation for the lithium atom has not been found. However, various approximations, such as the Hartree–Fock method, can be used to estimate the ground state energy and wavefunction of the atom. The quantum
Vector model of the atom Vector model of the atom In physics, in particular quantum mechanics, the vector model of the atom is a model of the atom in terms of angular momentum. It can be considered as the extension of the Rutherford-Bohr-Sommerfeld atom model to multi-electron atoms. The model is a convenient representation of the angular momenta of the electrons in the atom. Angular momentum is always split into orbital L, spin S and total J: Given that in quantum mechanics, angular momentum is quantized and there is an uncertainty relation for the components of each vector, the representation turns out to be quite