120 likes | 260 Views
Bohr ing Model of the Atom. Check HWK Theory of Atomic Spectra Practice Problem Work on next assignment. An explanation of Atomic Spectra. Consider where the electron starts When we write electron configurations we are writing the lowest energy.
E N D
Bohring Model of the Atom • Check HWK • Theory of Atomic Spectra • Practice Problem • Work on next assignment
An explanation of Atomic Spectra • Consider where the electron starts • When we write electron configurations we are writing the lowest energy. • The energy level and electron starts from is called its ground state.
Where the electron starts • When we write electron configurations we are writing the lowest energy. • The energy level and electron starts from is called its ground state.
Changing the energy • Let’s look at a hydrogen atom
Changing the energy • Heat or electricity or light can move the electron up energy levels
Changing the energy • As the electron falls back to ground state it gives the energy back as light
Changing the energy • May fall down in steps • Each with a different energy
{ { {
Ultraviolet Visible Infrared • Further they fall, more energy, higher frequency. • This is simplified • the orbitals also have different energies inside energy levels • All the electrons can move around.
Ultraviolet Visible Infrared • Bohr Model of Hydrogen Atom (1914) • Explain line spectra – e- orbiting nucleus • En = (-Rh) (1/n2) Rh=Rydberg constant = 2.18 x10-18 J n = Principle Quantum Number
E= (-Rh) (1/ 2) = 0 • E = Ef – Ei = h • = E h = (Rh)( 1/ni2 - 1/nf2 ) h ni>nf (-) emitted nf>ni (+) absorbed
Rh = 2.18 x10-18 J = (Rh)( 1/ni2 - 1/nf2 ) h Sample Problem h=6.626 x10-34J•s • Calculate the wavelength of light involved in the transition from n=4 to n=2. • Is this light absorbed or transmitted? = -6.17 x1014 1/s = 486 nm (violet) The light is given off or emitted.