Niels bohr, danish physicist, used the planetary model of the atom to explain the atomic spectrum and size of the hydrogen atom. The hydrogen emission spectrum comprises radiation of discrete frequencies. In this experiment the wavelengths of the visible emission lines of hydrogen balmer series will be measured and compared to the values predicted by bohr s quantum theory. The theoretical description of the hydrogen energy levels uses four parameters. Hydrogen spectrum balmer series, definition, diagram. The balmer equation is used to describe the four different wavelengths of hydrogen which are present in the visible light spectrum. Absorption spectrum observed when white light is passed through a cold atomic gas. The theoretical description of the hydrogen energy levels uses four. Bohrs characteriza tion of the hydrogen atom, the general achievement of the new quantum. This theory is based on a supposed analogy between the hydrogen spectrum.
His many contributions to the development of atomic physics and quantum mechanics, his personal influence on many students and colleagues, and his personal integrity, especially in the face of nazi oppression, earned him a prominent place in history. This absorption spectrum will contain dark spectral lines where the light has been absorbed by the atoms in our cell, illustrated in fig. Gases at surface absorb light at characteristic wavelengths. When a hydrogen atom absorbs a photon, it causes the electron to experience a transition to a higher energy level, for example, n 1, n 2. The movement of electrons between these energy levels produces a spectrum. The first person to realize that white light was made up of the colors of the rainbow was isaac newton, who in 1666 passed sunlight through a narrow slit, then a prism, to project the colored spectrum on to a wall. The bohr model and all of its successors describe the. The energy of the electron in a particular orbit of hydrogen atom could be calculated by bohr s theory. The genesis of the quantum theory of the chemical bond.
The bohr model of the atom, a radical departure from earlier, classical descriptions, was the first that incorporated quantum theory and was the predecessor of wholly quantummechanical models. Hydrogen atoms in a discharge lamp emit a series of lines in the visible part of the spectrum. Before arriving to us the light passes through surface of stars. Emission spectrum from a hot atomic gas vapor could also be electrically excited. Pdf precision spectroscopy of atomic hydrogen researchgate. How bohr s model of hydrogen explains atomic emission spectra. Therefore, we detect all the wavelengths but the one absorbed. The energy expression for hydrogen like ions such as he, li can be written as. According to the quantum theory of niels bohr 19, the hydrogen atom can only exist in. Bohr model, description of the structure of atoms, especially that of hydrogen, proposed 19 by the danish physicist niels bohr. Bohr model radii derivation using physics bohr model radii. It wasnt until the 1920s that a satisfactory theory for explaining the spectral properties of even the simplest element hydrogen. Measuring the positions of the spectral lines remains today a significant test of the predictions of the quantum theory. Bohrs model of atom and explanation of hydrogen spectra.
This paper proposes a reconstruction of 19 bohr s theory of the hydrogen atom in the framework of the modeltheoretic approach of theories. Bohr model energy levels derivation using physics bohr model energy levels. Pdf precise determinations of transition frequencies of simple atomic systems are. Precision spectroscopy of atomic hydrogen iopscience.