3.4 The Hydrogen Spectrum and the Bohr Model Flashcards
Formulated an empirical equation that accurately predicted the wavelengths of the four brightest atomic emission lines in the visible spectrum of hydrogen.
Johann Balmer
Balmer’s Equation
λ = 364.56nm • (m2/ (m2-n2)
where m is an integer greater than 2 and n=2
Rydberg’s constant, Rh
1.0974 x 107m-1
Rydberg’s Equation
Proposed a model for the hydrogen atom in which the electron revolves around the nucleus in one of an array of concentric orbits.
Niels Bohr
In this model orbits farther from the nucleus have larger values of n, and the electrons in them have higher (less negative) energies.
Bohr Model
The energy difference equation
E=-2.178 x 10-18J • (1/n2)
E=-2.178 x 10-18J • [(1/n2)2-(1/n2)1]
Which orbit represents the discrete energy orbit closest to the nucleus and also had the lowest (most negative) energy.
n=1
Calculate the energy, in joules, required to ionize a hydrogen atom when its electron is initially in the n =6 energy level. The energy needed to ionize a ground-state hydrogen atom is 2.18 x 10-18 J.
Using
E=-2.178 x 10-18J • [(1/n2)2-(1/n1)1]
E=-2.178 x 10-18J • [(1/inf2)-(1/62)]
=-2.178 x 10-18J •(-1/62)
=6.06 x 10-20J
Movement of an electron between any two energy levels
Electron transistion
Any energy state above ground state
Excited State
What is the wavelength, in nanometers, of the bright line of the hydrogen emission spectrum corresponding to the following transition?
n= 4 to n=3
Using
1/ λ = 1.0974 x 10-2nm-1[(1/n<span>1</span>)1-(1/n2)2]
= 1.0974 x 10-2nm-1•(1/32-1/42)
=5.33 x 10-4• 1/nm
λ=1.875 x 103nm
=1875nm
The presence of intense lines in the spectra of a number of metals is the basis for __________.
flame tests
Any emission from n = 5,4,3,,2 to n=1 is in what color range?
ultraviolet range
Any emission from n=5,4 to n=3 is in this range?
infrared range
